Troubleshoot OAuth/OIDC Issues on Confluent Cloud

This guide helps you diagnose and resolve common OAuth/OIDC authentication issues when connecting to Confluent Cloud.

Debug overview

Use this quick checklist before deep-diving into specific errors:

  • Enable client debug logging for your language and capture logs to a file (see Enable debug logging).

  • Check Confluent Cloud audit logs for OAuth authentication events to verify identity pool matching and authentication outcomes (see Use Confluent Cloud audit logs for OAuth debugging).

  • Sanity-check client configuration: bootstrap servers, sasl.mechanism, token endpoint URL, and OAuth-specific properties (see Correct Configuration Issues).

  • Retrieve a token with curl using the client credentials grant. Distinguish 4xx (misconfiguration/permission) vs 5xx (provider/network) responses (see Token inspection).

  • Decode the JWT and verify claims: iss and aud match your pool filter, exp/iat are valid, clock skew is minimal (preferably < 300 seconds) (see Token inspection).

  • Provider specifics:

    • Microsoft Entra ID: request v2 tokens; use scope=api://<clientId>/.default.

    • Okta: use the correct authorization server (often /oauth2/default).

  • Network/TLS: validate DNS, connectivity, and certificate chain from the client to the token endpoint (see Resolve Network and Connectivity Issues and Network diagnostics).

  • Error triage (see Analyze Errors):

  • For what to include in support requests, see Get help.

For OAuth client configuration by language, see Configure Kafka Clients for OAuth 2.0 Authentication in Confluent Cloud.

Information to collect for troubleshooting

Gather the following artifacts to streamline diagnosis (redact secrets when sharing):

  • Client configuration: the exact OAuth/OIDC properties used by the client

  • A representative JWT access token and its decoded claims (issuer, audience, expiry, relevant custom claims)

  • The identity pool ID and its filter expression, if using identity pools

  • Recent audit log entries showing OAuth authentication events (see Use Confluent Cloud audit logs for OAuth debugging)

For steps to obtain and inspect tokens and to validate token endpoints, see Token inspection and Network diagnostics.

Common issues and solutions

Diagnose and Resolve Common Issues

Troubleshoot Authentication Failures

Symptoms

  • Client fails to connect with authentication errors.

  • Invalid credentials or Authentication failed messages.

  • Connection timeouts during authentication.

Invalid client credentials

Cause

Incorrect client ID or client secret

Solution

  • Verify client ID and secret match your identity provider configuration.

  • Check for typos or extra whitespace in credentials.

  • Ensure credentials are properly URL-encoded if needed.

Debug steps

  • Enable debug logging to see the exact credentials being sent.

  • Test credentials directly with your identity provider’s token endpoint.

Incorrect token endpoint URL

Cause

Wrong or inaccessible OAuth token endpoint

Solution

  • Verify the token endpoint URL is correct and accessible.

  • Check network connectivity to the endpoint.

  • Ensure the endpoint supports the client_credentials grant type.

Debug steps

  • Test the endpoint with curl or Postman.

  • Check firewall rules and network access.

Token expiration issues

Cause

Tokens expiring before refresh or invalid expiration handling.

Solution

  • Implement proper token refresh logic.

  • Set appropriate buffer time before token expiration.

  • Monitor token lifecycle and refresh cycles.

Debug steps

  • Check token expiration times in JWT payload.

  • Verify refresh logic is working correctly.

Resolve Network and Connectivity Issues

Symptoms

  • Connection timeouts

  • Network unreachable errors

  • SSL/TLS handshake failures

Firewall or network restrictions

Cause

Network policies blocking OAuth endpoint access

Solution

  • Configure firewall rules to allow access to OAuth endpoints.

  • Check corporate proxy settings.

  • Verify DNS resolution for OAuth domains.

Debug steps

  • Test connectivity with ping, telnet, or curl.

  • Check network logs for blocked connections.

TLS certificate issues

Cause

Invalid or expired TLS certificates on OAuth endpoints

Solution

  • Verify TLS certificate validity.

  • Update certificate authorities if needed.

  • Check for certificate chain issues.

Debug steps

  • Test TLS connection with openssl.

  • Check certificate expiration dates.

DNS resolution problems

Cause

Unable to resolve OAuth endpoint hostnames

Solution

  • Verify DNS configuration.

  • Check for DNS caching issues.

  • Ensure proper hostname resolution.

Debug steps

  • Test DNS resolution with nslookup or dig.

  • Check /etc/hosts file for incorrect entries.

Correct Configuration Issues

Symptoms

  • Configuration parsing errors

  • Missing required parameters

  • Invalid parameter values

Missing required parameters

Cause

Incomplete OAuth configuration

Solution

  • Ensure all required parameters are specified.

  • Check parameter names and values.

  • Verify logical cluster ID and identity pool ID.

Debug steps

  • Review configuration against parameter reference.

  • Check for typos in parameter names.

Invalid parameter values

Cause

Incorrect parameter formats or values

Solution

  • Verify parameter value formats.

  • Check for proper URL encoding.

  • Ensure boolean values are correct.

Debug steps

  • Validate parameter values against expected formats.

  • Check for encoding issues.

JAAS configuration errors

Cause

Malformed JAAS configuration string

Solution

  • Verify JAAS configuration syntax.

  • Check for proper escaping of special characters.

  • Ensure all required JAAS parameters are present.

Debug steps

  • Parse JAAS configuration manually.

  • Check for syntax errors.

Address Identity Provider Issues

Symptoms

  • Identity provider authentication failures

  • Incorrect token claims or scopes

  • Authorization denied errors

Incorrect identity provider configuration

Cause

Mismatch between client and identity provider settings

Solution

  • Verify identity provider configuration

  • Check client registration settings

  • Ensure proper redirect URIs and scopes

Debug steps

  • Review identity provider logs

  • Check client registration details

Token claim issues

Cause

Missing or incorrect JWT claims

Solution

  • Verify required claims are present in tokens

  • Check claim values and formats

  • Ensure proper audience and issuer values

Debug steps

  • Decode and inspect JWT tokens

  • Verify claim values against expectations

Scope and permission issues

Cause

Insufficient permissions or incorrect scopes

Solution

  • Verify required scopes are requested

  • Check identity provider permission settings

  • Ensure proper role assignments

Debug steps

Apply Debugging Techniques

Enable debug logging

Java client debug logging

# Kafka client and OAuth debug logging
log4j.logger.org.apache.kafka.clients.NetworkClient=DEBUG
log4j.logger.org.apache.kafka.common.security.oauthbearer=DEBUG
log4j.logger.io.confluent.kafka.clients.oauth=DEBUG

Python client debug logging

import logging

# Enable librdkafka debug logging
logging.basicConfig(level=logging.DEBUG)

# Enable OAuth callback debugging
def debug_oauth_callback(args, config):
    print(f"OAuth callback called with args: {args}")
    # ... rest of callback implementation

Go client debug logging

// Enable librdkafka debug categories
config := &kafka.ConfigMap{
    // ... your OAuth config
    "debug": "security,protocol,broker",
}

JavaScript client debug logging

// Kafka client
const debugConfig = {
  ...producerConfig,
  debug: 'security,protocol,broker'
};

.NET (C#) client debug logging

// Enable debug logging
var config = new ProducerConfig
{
    // ... other config
    Debug = "all"  // Enable all debug categories
};

Inspect Tokens

Token inspection

Decode JWT tokens

import jwt
import json

def inspect_token(token):
    """Decode and inspect JWT token."""
    try:
        # Decode without verification for inspection
        decoded = jwt.decode(token, options={"verify_signature": False})
        print("Token Header:", json.dumps(decoded['header'], indent=2))
        print("Token Payload:", json.dumps(decoded['payload'], indent=2))
        return decoded
    except Exception as e:
        print(f"Error decoding token: {e}")
        return None

Check token expiration

import time

def check_token_expiration(token_data):
    """Check if token is expired or near expiration."""
    exp = token_data.get('exp')
    if exp:
        current_time = int(time.time())
        time_until_expiry = exp - current_time
        print(f"Token expires in {time_until_expiry} seconds")
        return time_until_expiry > 300  # 5 minute buffer
    return False

Run Network Diagnostics

Note

If client and server clocks differ significantly (for example, more than 5 minutes), OIDC token validation may fail due to iat/exp claim checks. Ensure system time is synchronized (for example, via NTP) on client hosts.

Network diagnostics

Test OAuth endpoint connectivity

# Test basic connectivity
curl -I https://your-oauth-endpoint.com/oauth2/token

# Test token endpoint with credentials
curl -X POST https://your-oauth-endpoint.com/oauth2/token \
  -H "Content-Type: application/x-www-form-urlencoded" \
  -d "grant_type=client_credentials&client_id=your-client-id&client_secret=your-client-secret"

Check SSL certificate

# Check SSL certificate
openssl s_client -connect your-oauth-endpoint.com:443 -servername your-oauth-endpoint.com

# Check certificate chain
openssl s_client -connect your-oauth-endpoint.com:443 -showcerts

Note

If you encounter an error such as error setting certificate file: /etc/pki/tls/certs/ca-bundle.crt (-1), verify that the system CA certificate bundle is installed and accessible. On some platforms you may need to set an environment variable to point to the CA bundle (for example, SSL_CERT_FILE or REQUESTS_CA_BUNDLE) or install/update CA certificates.

DNS resolution

# Check DNS resolution
nslookup your-oauth-endpoint.com
dig your-oauth-endpoint.com

# Check for DNS issues
traceroute your-oauth-endpoint.com

Analyze Errors

Common error messages and solutions

“Invalid credentials”

  • Check client ID and secret.

  • Verify identity provider configuration.

  • Ensure proper URL encoding.

“Token endpoint not found”

  • Verify token endpoint URL.

  • Check network connectivity.

  • Ensure endpoint supports client_credentials grant.

“Token expired”

“Invalid token format”

  • Verify JWT token structure.

  • Check token encoding.

  • Validate token claims.

  • If your token includes a cty header of JWT, validation libraries may expect a nested JWT. Either omit cty or set it to JSON unless you are intentionally using nested tokens.

“Authorization denied”

  • Check identity pool configuration.

  • Verify token claims match pool filters.

  • Ensure proper permissions.

Use Confluent Cloud audit logs for OAuth debugging

Confluent Cloud audit logs provide valuable insights into OAuth authentication events, helping you diagnose identity pool filter matching issues and authentication failures. Confluent Cloud audit logs capture the authentication outcome but not the raw JWT token contents for security reasons.

Access Confluent Cloud audit logs

To access and consume Confluent Cloud audit logs for OAuth troubleshooting, see Access and Consume Audit Logs on Confluent Cloud for complete setup and consumption instructions. Confluent Cloud audit logs are automatically enabled for Standard, Enterprise, Dedicated, and Freight clusters and contain OAuth authentication events in the confluent-audit-log-events topic.

OAuth authentication information in audit logs

For OAuth authentication events, audit logs contain the following key information in the authenticationInfo section:

Principal and Identity Information:

"authenticationInfo": {
  "principal": {
    "identity_pool": {
      "resource_id": "pool-1"
    }
  },
  "identity": "crn://confluent.cloud/organization=org-id/identity-provider=op-1/[email protected]",
  "result": "SUCCESS",
  "metadata": {
    "mechanism": "SASL_SSL/OAUTHBEARER",
    "identifier": "client-identifier"
  }
}

Key fields for troubleshooting:

Field

Troubleshooting Use

result

Shows SUCCESS or failure status of authentication

identity_pool.resource_id

Indicates which identity pool was matched (if any)

identity

Shows the extracted identity value based on the identity claim configuration

metadata.mechanism

Confirms SASL_SSL/OAUTHBEARER for OAuth authentication

requestId

Helps correlate multiple audit events for the same request

Troubleshooting identity pool filter issues

Scenario 1: Authentication fails completely

If you see no OAuth authentication events in audit logs:

  • Verify your client is reaching Confluent Cloud (check network connectivity)

  • Confirm OAuth client configuration is correct

  • Enable client debug logging to see token request/response details

Scenario 2: Authentication succeeds but wrong identity pool

If audit logs show a different identity_pool.resource_id than expected:

  • Review all identity pool filters in your identity provider

  • Check if multiple pools have overlapping filter criteria

  • Verify token claims match your intended pool’s filter expression

  • Consider using more specific filter expressions

Scenario 3: Identity extraction issues

If the identity field shows unexpected values:

  • Check the identity provider’s identity_claim configuration

  • Verify your JWT token contains the expected claim (use Token inspection)

  • Ensure the claim value format matches your expectations

Scenario 4: Auto pool mapping not working

For auto pool mapping troubleshooting:

  • Verify audit logs show the expected identity pools being matched

  • Check that client configuration omits extension_identityPoolId

  • Confirm multiple pools aren’t conflicting with each other

Combining audit logs with token inspection

For comprehensive troubleshooting, use audit logs together with manual token inspection:

  1. Check audit logs to see the authentication outcome and which identity pool was matched

  2. Decode the JWT token (see Token inspection) to inspect the actual claims

  3. Compare token claims with your identity pool filter expressions

  4. Verify claim extraction by checking if the audit log identity field matches the expected claim value from your token

Example troubleshooting workflow:

  1. Access audit logs: Follow Access and Consume Audit Logs on Confluent Cloud to set up audit log consumption

  2. Filter OAuth events: Search for SASL_SSL/OAUTHBEARER mechanism in authentication events

  3. Decode JWT token: Use Token inspection to inspect token claims

  4. Compare and correlate: Match token claims with pool filter expressions and verify the audit log identity field matches your expected claim value

Limitations of audit log debugging

Audit logs do not contain:

  • Raw JWT token contents (for security reasons)

  • Detailed filter evaluation steps

  • Token validation failure reasons

  • JWKS validation details

For these details, use client debug logging and manual token inspection as described in Enable debug logging and Token inspection.

Set up Monitoring and Alerts

Key metrics to monitor

  • Authentication success rate

    • Track successful vs failed authentication attempts

    • Monitor authentication latency.

    • Alert on authentication failures.

  • Token refresh cycles

    • Monitor token refresh frequency.

    • Track token expiration times.

    • Alert on token refresh failures.

  • Network connectivity

    • Monitor OAuth endpoint availability.

    • Track connection latency.

    • Alert on connectivity issues.

  • Error rates

    • Monitor authentication error types.

    • Track configuration errors.

    • Alert on increased error rates.

Log analysis

# Search for authentication errors
grep "authentication failed" kafka-client.log

# Search for token refresh issues
grep "token refresh" kafka-client.log

# Search for network errors
grep "connection timeout" kafka-client.log

Get help

If you’re unable to resolve OAuth issues using this troubleshooting guide:

  1. Collect diagnostic information:

    • Enable debug logging.

    • Gather error messages and logs.

    • Document configuration settings.

    • Note the exact steps to reproduce the issue.

  2. Check documentation:

    • Review identity provider documentation.

    • Consult Confluent Cloud OAuth documentation.

    • Check for known issues or limitations.

  3. Contact Confluent Support:

    • Open a support request in the Confluent Support Portal.

    • Provide detailed error information.

    • Include relevant logs and configuration.

    • Describe the troubleshooting steps already taken.

  4. Community resources:

Information to include in support requests

  • Client type and version (Java, Python, C#, Go, JavaScript, .NET).

  • Identity provider type and version, and the token endpoint URL used.

  • Complete error messages and stack traces.

  • Relevant client OAuth/OIDC configuration properties (with sensitive data redacted).

  • Identity pool ID and pool filter expression (if using identity pools).

  • A representative JWT access token with decoded header and payload (with sensitive values redacted); see Token inspection.

  • Recent audit log entries showing authentication events (see Use Confluent Cloud audit logs for OAuth debugging).

  • Steps to reproduce the issue.

  • Debug logs and token inspection results.

  • Network connectivity test results; see Network diagnostics.