Hey, @foss4ever,
Glad you’ve come to Open Community for help. We have several practitioners here, who, like you, use Graylog as an important tool . Look forward to those responses to your question.
The issue might be your certificates. I’ll start by asking, have you checked the certificates and their trust chain?
It’s possible that the warnings in the server logs might indicate that the Graylog server is unable to find a valid certification path to the target and therefore is unable to call these resources. I’m guessing this because it may be that TLS-enabled Beats inputs are failing to start, even though log data is still coming in and processed by Graylog. This might be due to a problem with the certificate or the certificate chain not being recognized by the updated version of Graylog.
Just a guess.
You may want to check posts like this in the community:
Other thoughts?