Why is this happening? I do not see a stack trace in the server log and if my users register 'normally', they do receive the mails, so there is nothing wrong with the mail options... If you login with Twitter, it says that you have to confirm your mail, which is fine, but the mail never gets in the inbox / spambox etc. Is this a familiar problem? If so, how can I solve it? PS: Facebook login works. But that does not require a confirmation mail. Can I make that happen for Twitter too?