Troubleshoot common Crisp knowledge base issues, including custom domains, article visibility, cache, SSL, and error pages.

Most knowledge base issues come from DNS configuration, category visibility, short cache delays, or SSL provisioning after a custom domain change. Use the sections below to identify which layer needs attention.

Custom knowledge base domain is rejected

When you configure a custom knowledge base domain, Crisp provides DNS records that must be added to your domain provider. If validation fails, Crisp keeps showing the records that are still invalid while hiding records that already validate correctly.

What to check:

• DNS values → copy the records exactly as shown in Crisp
• Propagation time → if your DNS TTL is high, wait before validating again
• CNAME dots → advanced DNS systems such as BIND may require a trailing dot at the end of CNAME targets
• Cloudflare proxy → disable proxy mode for the validation record and use DNS-only mode

Articles or categories are not updated

The Crisp knowledge base uses a short cache on categories, articles, and the homepage. If you update content and refresh immediately, the public page may still show the previous version for a few seconds.

Wait briefly, then refresh again. If your own browser still shows the old content, test from a private browser window or clear the browser cache.

Article is not listed publicly

An article without a category cannot appear in public category navigation or on the knowledge base homepage. The article may still be accessible from its direct public link, search engines, or knowledge base search.

To list the article publicly:

1. Go to Crisp
2. Open your knowledge base articles
3. Edit the article
4. Assign it to a public category
5. Save and wait for the cache to refresh

Knowledge base shows a Crisp error page

If the knowledge base is misconfigured or temporarily unavailable, Crisp can show an error page. The error code usually indicates whether you can fix it yourself or whether Crisp needs to intervene.

Yellow errors

Yellow errors usually require an action on your side.

Common yellow errors:

• Error 400 → the browser made a bad request
• Error 402 → the knowledge base plugin is inactive and needs to be re-enabled
• Error 403 → the knowledge base is not allowed for the current request
• Error 408 → the request took too long because of browser or network conditions
• Error 410 → no knowledge base exists for the requested domain
• Error 412 → the knowledge base is not configured yet; add at least one language
• Error 420 → the network sent too many requests and was temporarily blocked
• Error 429 → the network sent too many requests and was temporarily rate-limited

Red errors

Red errors indicate a Crisp-side issue or temporary platform problem. Crisp monitors these errors, but you should contact support if a red error stays visible for more than a few minutes.

Common red errors:

• Error 500 → a rendering bug occurred
• Error 502 → the knowledge base system is temporarily unavailable
• Error 503 → the knowledge base system is temporarily unavailable or in maintenance
• Error 504 → the knowledge base system timed out or is temporarily unavailable

Knowledge base shows an SSL warning

When you add or change a custom knowledge base domain, Crisp needs to request and provision an SSL certificate for that domain. This usually takes about a minute and can take up to a few minutes.

Browsers can also cache SSL sessions, so an SSL warning may persist locally even after the certificate is ready.

What to do:

1. Wait a few minutes after changing the domain
2. Open the knowledge base in a private browser window
3. Restart the browser if the old SSL state is cached
4. Contact Crisp support if the warning persists on a domain that was already working for a long time

Updated on: 03/05/2026