Plex Account Sign in issues.

Hi Guys,

Recently I have got an error message when I try to Sign in to my Plex account from all my devices at home.
The error is something like :“Sorry It is temporarly not possible to reach our servers, try again”.
It looks like the problem is a setup of the router because it happens with all devices behind the router and If i connect the devices without router (i.e. with a 4g modem or a phone in thetering mode) they log in perfectly.
The issue is only related to the Plex account sign in phase. Once this is done, I do not have any issue in accessing my media server.
Port 32400 is open with port forwarding even if in theory this is necessary only for remotely access to the media server which is not a function I’m interest for the moment.
I tried to disable the router firewall too but without success.
Any suggestion?
Thanks for your support.
Massimiliano