Hi,
When trying to create a MATE forum account using Yahoo or Twitter I get an error message. (Unable to share screenshot as I am a new user).
ERROR 502 bad gateway.
Managed to connect using Google account in the end.
Cheers
Phil
These errors doesn’t leave a good impression for new users. 
I believe @wimpy is in charge of the forums, he should be able to correct the bad gateway. 
I thought there may be a way to link/unlink new accounts on these forums, but I can’t seem to find an option? 