I use Thunderbird as the email client. I have a .com domain and have email forwarding so that emails sent to my domain email address are sent to my TalkTalk (Pipex) account email.
Thunderbird is set to send email messages using the domain email address and it has all been working absolutely fine for years.
But three days ago it has stopped sending messages with the error:
Sender address rejected: not owned by user 3@10137431
However, if I change the email address in Thunderbird's account settings back to my Pipex email address, it will send out the email message. But of course the recipient sees that it has come from the Pipex address, and not the .com address. Which is not what I want.
This has only been happening for the past three days. Has something changed?
