When I submit some basic changes such as email address for me - the Admin of the Forum, I get the following eror:
========================= There Was A Problem With Your Details
Your request was not sent due to the following error: The server rejected the sender address. The server response was: 530 5.7.0 Must issue a STARTTLS command first 6sm5047167nzn =========================
Looks like your mail server has problems. To change the email address, while the problems aren't fixed turn email validation off, change the address and then turn email validation on again.
I now have the mail server issue to resolve. The info in the relevant section of the forum here hasn't been of help to me. That's because I'm not technical - but I'm trying! :-)