Quick outline - We are a small charity with our SMTP server on a BTNet Leased Line.
For some months now we have not been recieving emails sent from other companies using BT's services e.g. btinternet.com email addresses or where they have their SMTP server on a BT line. We have no issues recieving mail from any other accounts/scenarios and our SMTP server checks out with no errors.
I logged this with BT direct around 6 weeks ago but as we are not using their relay servers they cannot help us and direct us to other internal departments who only communicate via email.
Any advice would be hugely appreciated. My thoughts are that filters are incorrect on our managed router.
NDR the senders are reporting is:
EXCHANGE.Domain.Local #550 4.4.7 QUEUE.Expired; message expired
