Wrong or missing login data when sending - Paid account
"Wrong or missing login data to access mail transport server smtp.mailbox.org."
I know this has been asked before, but according to some of those posts, this is apparently a problem with the spam filter, and not any setting I have control over.
It is disappointing that this issue only arose after paying for the service.
If there's anything I should do, let me know, else I will just wait.