I am receiving all emails to this slave email with no issues however I have been unable to reply to or send any emails for 3 weeks on all devices, when using TPG post office I am getting the error message "Failure sending message: Email address not valid. Please use an email address which looks like firstname.lastname@example.org" when attempting to reply to valid addresses.
I have changed my password with no improvement. Are you able to assist further?
Thanks in advance.