troubleshooting
Articles about troubleshooting from the Skycloak team.
Connect claude.ai to Keycloak with CIMD: Fix the JWT Grant Error
claude.ai fails on Keycloak CIMD with a JWT grant error in public clients. Here is the tested fix: Keycloak 26.8,…
7 min read
Keycloak 26.8.2 Admin API Returns 401 for Service Accounts: The kc-admin-api Scope Fix
After upgrading to Keycloak 26.8.2, service account tokens get 401 from the Admin REST API. Why the new audience check…
7 min readWhy Your Custom Keycloak Attribute Isn't in the Token
Fix custom Keycloak user attributes missing from tokens: add a protocol mapper, declare the attribute in User Profile (v24+), and…
9 min readWhy Keycloak Logins Get Slow With Lots of Groups (and How to Fix It)
Fix slow Keycloak logins caused by many groups or roles: how group and role resolution works, why it scales poorly,…
12 min readRevoke One Keycloak Session Without Logging the User Out Everywhere
Revoke a single Keycloak session or refresh token without ending all of a user's sessions: the logout endpoint, admin session…
9 min readFixing Keycloak's 431 'Request Header Fields Too Large'
Fix Keycloak HTTP 431 'Request Header Fields Too Large' errors: raise Quarkus header limits and shrink bloated tokens by trimming…
11 min readKeycloak 'Token Not Active' Clock Skew: How to Fix
Fix Keycloak 'token is not active' and 'JWT issued in the future' errors caused by clock skew: sync server time…
7 min readKeycloak 'Account Already Exists' During Identity Brokering
Fix the Keycloak 'account already exists' error during social login and identity brokering: the first-login flow, account linking, and trusting…
10 min readKeycloak Theme Not Loading: Causes and Fixes
Fix Keycloak custom themes not loading: theme caching, the themes directory and provider structure, theme selection, and Quarkus dev vs…
9 min readKeycloak Not Sending Emails? How to Fix It
Fix Keycloak email problems: SMTP configuration, TLS/SSL ports, authentication, the 'from' address, app passwords, and testing from the admin console.
10 min readStay ahead on identity & security
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