Learn Authentik - Troubleshooting & Debugging

#Introduction

In episode 27, you closed as many security gaps as possible. But no system is problem-free forever — applications change, dependencies change, and a config that looks right can fail on a certain combination. When problems arise, your quality as an operator is tested not by how fast you memorize solutions, but by how systematically you investigate.

Think of troubleshooting like a doctor's diagnosis: a doctor doesn't guess medicine from a single symptom, they gather history, check vital signs, then narrow down the cause. This episode teaches that mindset for Authentik: start with logs, recognize the six most common problems, use the flow inspector, and know when to ask the community.

#Logs: The Starting Point of Every Investigation

All answers begin with logs. Authentik writes structured logs to stdout — the same place you can stream from Compose or Kubernetes:

docker compose logs -f server worker

Server pod logs in Kubernetes

kubectl logs -n authentik deploy/authentik-server

Understand the division of labor before reading: the server records all HTTP traffic — incoming requests, executed flows, errors from user requests. The worker records background tasks — failed emails, failed event processing, sync errors. If the problem is "email isn't sent", server logs won't answer it; check the worker. If the UI errors, check the server.

If regular logs aren't detailed enough, raise AUTHENTIK_LOG_LEVEL to debug temporarily (episode 25). Debug logs can be very noisy — enable them only for investigation and restore them afterwards. For more scannable log streams, combine with docker compose logs -f --since 10m server to only see the last ten minutes, and add --tail when you want to limit the number of lines.

#Common Problem #1: Error 500 on Every Page

All pages consistently showing 500 usually means one of three things: a disconnected database connection, migrations not finished, or an inconsistent AUTHENTIK_SECRET_KEY between pods. Check the server logs for database connection traces, and make sure migrations run fully at startup. Test the database connection directly to rule out networking:

docker compose exec postgresql psql -U authentik -d authentik -c "SELECT 1;"

If this command succeeds but Authentik still returns 500, point at the other two possibilities: migration status and secret key consistency between instances.

#Common Problem #2: Outpost Connection Refused / Offline

An outpost marked offline in the UI means it can't communicate with the Authentik API. The most common causes: wrong AUTHENTIK_HOST (the outpost doesn't know which address to contact), an expired or wrong service connection token, or a firewall blocking outbound connection from the outpost to the API. Test from the outpost side:

curl -fsS http://localhost:9000/outpost.goauthentik.io/ping

If the ping fails, check the outpost host configuration and renew the token via the outpost page in the admin. After the token is renewed, the outpost will reload its configuration — a process usually visible in worker logs.

#Common Problem #3: OIDC Redirect Error

Errors like redirect_uri does not match are the most commonly encountered in OIDC integration. Authentik matches redirect URIs strictly: scheme, host, port, and path must be identical. https://app.example.com/callback differs from http://app.example.com/callback — a single "s" that breaks login.

Also check two other things: time (a skewed server clock makes token verification fail — make sure NTP is running) and signing key (if the JWT key changed, applications holding the old key will reject new tokens). Compare the exact URI registered at the provider against what the application sends on login. For SPAs using PKCE, also make sure code_challenge is sent with the same method the provider supports — a method mismatch between plain and S256 is a rarely recognized cause of errors.

#Common Problem #4: SAML Attribute Mismatch

With SAML, the most common problem isn't authentication itself, but attributes. The user logs in successfully but the application doesn't recognize them — usually because the attribute name doesn't match, the NameID format differs, or the mapping is wrong (episode 14). Use a SAML tracer browser extension to see the assertion the application receives: compare the attribute names Authentik sends against what the application expects.

A failed signature error usually means a certificate mismatch: the service provider holds the old IdP certificate, or the metadata hasn't been re-imported. And don't forget the clock: SAML is very sensitive to time differences because assertions have a validity period.

#Common Problem #5: Database Connection

Database connection errors come in various faces: fe_sendauth: no password supplied (credentials not sent), connection refused (wrong host/port or database not up), or too many connections (the max_connections limit exceeded). For credentials, check the AUTHENTIK_POSTGRESQL__HOST variables, user, password, and make sure they match what's set in the database. For too many connections, consider a connection pooler like PgBouncer and check for piled-up idle connections.

#Common Problem #6: Session Issues

Users constantly being logged out usually trace back to cookies. Check AUTHENTIK_COOKIE_DOMAIN — a wrong cookie domain makes the browser reject cookies or send them to the wrong domain. Also be aware of browsers blocking third-party cookies: if Authentik runs on a different domain than the application, some browsers will block the cookies needed for forward auth. Finally, rotating AUTHENTIK_SECRET_KEY re-signs all sessions — users suddenly logged out en masse after an upgrade is a sign the key changed.

#Flow Inspector: A Microscope for Authentication Flows

When the problem is inside a flow, logs often aren't detailed enough. The flow inspector is the tool made exactly for this: it runs the flow step by step and shows every executed stage, the result of every policy, and the context passed through. Enable it from the flow page, then run the flow as the problematic user.

It's like watching a match replay in slow motion: you can see exactly which stage rejected, which policy returned False, and which field caused the flow to stop. For policies, also use the policy tester to evaluate expressions without running the full flow.

#Event Log: Evidence, Not Guesses

While the flow inspector answers how a flow runs, the event log answers what happened across the whole system. The Events menu in the admin stores login, logout, admin action, and failed authentication trails with their context — who, from which IP, when, and what the result was. This is the most reliable silent witness when chasing a "not everyone can log in, only some" problem.

Watch patterns in events: many failures from the same IP points to brute force or a firewall blocking a large NAT; consistent failures from a specific application point to a misconfiguration in that application's provider. For deeper investigation, events can also be pulled via the API using a token from episode 21 — curl -H 'Authorization: Bearer TOKEN' https://auth.example.com/api/v3/events/events/ — so they can be combined with external data.

Don't forget to check System Tasks: the list of scheduled tasks like synchronization and event cleanup running on the worker. Repeatedly failing tasks are the root of many "weird" problems — for example an LDAP sync that stopped makes new users not appear, or event cleanup that stopped makes the database bloat.

#Investigation Structure and When to Ask

Organize the investigation in this order: server logs → worker logs → health check → database → host configuration → flow inspector. Two questions narrow half the problems: "When did it last work?" and "What changed since then?" — upgrades, DNS changes, or key rotations are prime suspects.

If you have to ask the community, prepare good information: version (ak version), deploy method (Compose/Kubernetes), relevant error logs without sensitive data, and reproduction steps. A question with those three things gets answered far faster than "My Authentik is broken, help".

docker compose exec server ak version

The right channels: GitHub Issues for possible bugs (search first, don't ask about existing ones), the community Discord for discussion and quick help, and the constantly updated official documentation. The official documentation is the best learning curve — most "weird problems" turn out to be already-documented behavior.

Finally, get into the habit of documenting every problem you've solved. A runbook with symptoms, causes, and solutions will feel useless until the same problem appears two months later — and that's when you thank yourself. The only discovery more valuable than a solution is a solution that doesn't need to be discovered twice.

#Closing

In this episode 28, you learned to investigate Authentik problems systematically: reading server and worker logs with an understanding of their division of labor, handling six common problems from 500 errors, offline outposts, rejected OIDC redirects, mismatched SAML attributes, database connections, to session issues — plus using the flow inspector and policy tester for in-flow investigation, and knowing how to ask the community with sufficient information.

Key takeaways:

• Start with logs; distinguish server vs worker problems from the start.
• OIDC redirect URIs must match exactly; SAML is sensitive to attributes and the clock.
• The flow inspector and policy tester turn guesses into evidence.
• Always ask two questions: when did it last work, and what changed.
• A good community report includes the version, deploy method, and relevant logs.

Once your Authentik runs smoothly, the next question is what if you're coming from another system. In episode 29, we cover Migration from Other IdPs: moving from Keycloak, Authelia, or Dex gradually, exporting users and groups, leveraging LDAP/AD sync, rebuilding providers via blueprints, swapping applications one by one, and designing a safe cutover and rollback. See you in episode 29!