We were alerted of the issue at 16:59 to our Mail Delivery System rejecting emails being sent from our domain.
Whilst we were still able to receive emails, we could not reply back to them.
During our investigation, we discovered that one of our DNS records had been changed to ‘Proxy’ instead of ‘DNS only’.
At 18:12, our system was restored back to an operational state. We will continue to monitor it’s performance throughout the day.