Sorry for posting a question about access to another forum.

I need help with a Thunderbird set-up but am unable to log in to the Mozilla Thunderbird support forum. I must have used the forum years ago because my email address is already registered with them but I can't remember my username. It seems that there is no way to retrieve this situation because to get the activation email resent, you have to know the username.
To get a password resent, you must know your username
You can't re-register because the email address is already used.

Anybody have any ideas?