Activation failed - Internal error: HTTPConnectionPool Read timed out

CMK version: CME 2.4.0p16
OS version: CMK Virt Appliance 1.7.13

Error message: Internal error: HTTPConnectionPool(host=‘10.x.x.x’, port=80): Read timed out. (read timeout=None)

Output of “cmk --debug -vvn hostname”: (If it is a problem with checks or plugins)

Hello all,

I’m currently having an issue where, on one of about 40 sites, I can no longer activate changes after uploading a plugin.
After starting the activation process, I only see “Synchronizing” until the above error appears after 15 minutes.

The site is hosted on an external remote server; the server is accessible and has already been rebooted. Distributed monitoring is still working normally with live status.

I first installed and activated a plugin, and it worked on all the other sites. After making a small correction, I re-uploaded the plugin with a new version number, activated it, and deactivated the old versions.
It works on all sites, except for this one.
The first version of the plugin is still present on the server, so it wasn’t synchronized.

Where should I start looking? I don’t see any irregularities in the logs that I can use as a starting point.

Thanks in advance!
Kind regards,
Marc