Users Sign-Up error - illegal character

I just added the Users capability to a new project. I am calling anvil.users.log_in_with_form().

When trying to sign-up as a new user, I get this error I have not seen before:

anvil.email.SendFailure: Domain contains illegal character <running on the server>

Interesting - could well be a bug, or could be that it’s correctly catching an incorrect email address but not handling the error very nicely. (Moved to Bug Reports.)

Are you getting this every time you try to sign-up? Are you able to tell me what email address you’re using (perhaps in a DM)?

Are you able to share a clone link so I can try?