Reverse proxy problems

Hi, we have been running Jenkins fairly successfully with the nginx reverse proxy but the nginx configuration seems to be causing some problems. To investigate, we disabled nginx but are now getting lots of these messages:

## HTTP ERROR 403 No valid crumb was included in the request

And ‘Manage Jenkins’ shows:

It appears that your reverse proxy set up is broken.

We have CSRF Protection > Crumb Issuer set to Default Crumb Issuer.

The setting of CSRF Protection > Crumb > Enable Proxy Compatibility seems to make no difference.

The log shows lots of errors like this:

Jun 08, 2023 1:50:23 PM WARNING doFilter

No valid crumb was included in request for /administrativeMonitor/hudson.diagnosis.ReverseProxySetupMonitor/test by admin. Returning 403.

Any suggestions how to fix this please?

Hello @DavidA2014 ,

To me, the It appears that your reverse proxy set up is broken. means the URL you use in your browser does not match with the one configured in Manage Jenkins/System/Jenkins URL.

Is your reverse proxy (in this case, nginx) properly configured to pass the necessary headers and cookies required for Jenkins’ CSRF protection?
As far as I know, you may need to ensure that the X-FORWARDED_FOR header is being correctly passed from the reverse proxy to Jenkins.