1.) When did the issue first happen? Were there any unusual things you can think of that happened near that time?
several months ago
2.) Do you see the issue on all characters on this account? Does it happen on other accounts also?
it has happened on 3 accounts of mine
3.) If you have more than one PC, does the issue still occur on a different PC?
yes it does
4.) Does the problem happen all the time or only sometimes? (We can see chat logs everyday showing up from the character in the correct chat channels).
yes those characters cannot chat at all for months now
5.) Have you tried to reinstall the game and testing it with the default settings?
this wont affect it since logging into a brand new computer has the same issue on those characters.
6.) Which OS and build version do you play on?
7 and 10