Not sure this issue is solved already or not, but i had problems registering here in forum. I did not receive the confirmation link even when testing at different occasion and emal addresses.
Maybe other have same issue when trying to join the forum.
So you succeeded to sign in with GitHub?
Anyway everyone has this issue 
: Can't sigh up to support.delta.chat (activation email not sent) · Issue #394 · deltachat/deltachat-android · GitHub and make codespeak.net serve as delta.chat MX · Issue #98 · deltachat/deltachat-pages · GitHub
I didnt sign in with Github.
I posted this issue in the IRC channel and someone may have manually activated my account as i was able to login without receiving the activation email.
Hope this can be solved as im sure more people would like to join the forum.
Maybe you could switch to invite option until this gets resolved, mods could then slowly start bring on new members with less trouble. I got a bit discouraged to try signing up again when the second attempt failed.
registration and e-mail notifications should be solved now, thanks for perservering!