Over the past 36 hours we have seen a number of different users, on a number of different servers, reporting issues with emails sent to BT Internet email addresses bouncing with the following message:

SMTP error from remote mail server after end of data:
554 Message rejected: Please check your DKIM entry in your DNS for the domain you are sending from. Guide for bulk senders www.bt.com/bulksender

Originally we thought this was an isolated issue but as more reports came in we realised the issue was widespread.

As such we reached out to some fellow web hosts and it turned out that their clients had also been getting the same bounce messages. So it appears that at the present time BT is bouncing any emails sent from any web host using cPanel server that have a DKIM record set up.

We are unsure what has caused BT to bounce messages from senders with correct DKIM records, but until BT sort their mailservers out, the only solution is to disable and then re-enable DKIM for your domains via cPanel > Email Authentication