I’ve had the issue with the latest version before the portal update, too. Now with Portal it looks just like your error on my site as well. I’m a bit confused wether “Please enter a valid email address” and “Failed to sign up, please try again” are words for the same error.
Since @Dinakar and me seem to have similar issues, I’ll post my ghost log
here, hoping we’ll figure it out:
NAME: EmailError
MESSAGE: Failed to send email. Reason: Sending failed with error 451.
It seems I have to check mailing setup. But as mentioned in my own post, this only seems to be an issue for some users, which seems weird. Shouldn’t signin just not work at all if it’s a mail misconfiguration?