I am sorry but each case needs to be investigated through diagnostics as they are not all the same underlying issue.
There have been two cases of problems when using Tautulli to monitor remote access asking plex.tv every minute to test the connectivity. It is possible that plex.tv servers could not handle the volume of requests from every Tautulli managed server doing a request every minute.
There was another to do with use of vpn and there was another to do with being connected through a CGNAT Public IP resulting in Double NAT and fixed after upgrading the ISP package to fix the public IP. Another was that a user replaced the server and forgot to update the port forward to switch it to the new server.
Please enable debug logging on the server.
See https://support.plex.tv/articles/201643703-reporting-issues-with-plex-media-server/
Restart the server to get fresh logs
Reproduce the problem
Note down the time when the issue arises and take screenshots
Collect the server logs - see https://support.plex.tv/articles/200250417-plex-media-server-log-files/
and if using a port forward get screenshots of the settings in the router for the port forward rule and the dhcp reservation for the server IP address
Thanks
