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Werk #20005: Agent updater: Show meaningful error when authentication to the central site fails

Component Agent bakery
Title Agent updater: Show meaningful error when authentication to the central site fails
Date Jul 21, 2026
Level Trivial Change
Class Bug Fix
Compatibility Compatible - no manual interaction needed
Checkmk versions & editions
3.0.0b1
Not yet released
Checkmk Pro, Checkmk Ultimate, Checkmk Cloud, Checkmk Ultimate MT
2.5.0p12
Not yet released
Checkmk Pro, Checkmk Ultimate, Checkmk Cloud, Checkmk Ultimate MT
2.4.0p36
Not yet released
Checkmk Pro, Checkmk Ultimate, Checkmk Cloud, Checkmk Ultimate MT

In distributed setups, an unauthenticated agent updater request forwarded to the central site was reported on the remote site as a misleading "Checkmk version mismatch?" error, because the central site answered with HTTP 200 and an HTML page that could not be parsed as JSON.

The central site now returns HTTP 401 for such requests, so the remote site surfaces a clear authentication error instead.

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