Had the issue today the certificate of my server expired and interrupted services. I fixed it with "ispconfig_update.sh --force" but how to make sure it updates in the future, this is first time it happened after upgrading to "Server: ms1.serverflex.co.za (Ubuntu 24.04.2 LTS (Noble Numbat)) ISPConfig 3.3.0p2"
Check the logs if you can find out why the automatic update did not work properly and always monitor your critical services.