Since about the 18th September 2018 BT have been having issues with emails being delayed for hours or not being sent at all!
We have now seen this first hand as customers are coming to us asking why this is happening.
Looking at the issue our mail servers are informing us that BT are failing SPF checks. These checks are sender policies checks, and the policies are created by BT and published to the internet for mail servers to use. Basically these policies state who is and who is not allowed to send using a BT address, and if someone not on this list tries they are a spammer.
This being honest seemed a little odd, a big company like this having all the tech guys they have getting something so simple wrong. So I manually checked against a couple of emails myself…
And BT have the wrong policies listed on line compared to what servers are trying to send emails as BT address like @btinternet.com
Having a quick search on the internet I found my good old Downdetector site which shows others stating the same too.
If your a BT customer and using their email platform, don’t expect people to receive your emails for a long time; and to our clients we are sorry but this is a BT issue that only they can solve as they write the policies our system(s)s stick to.
*** UPDATE ***
On 24/09/2018 we have looked at this issue again as we are still getting delayed messages or bouncing them due to SPF failures.
We have found that BT look like they now have correct record, this record calls multiple other records which do validate the recent sender servers but we are still rejecting them.
We have found that a DNS change or something from BT has not been accepted or read correctly but some DNS Services causing a time out looking up and reading all the SPF records.
This delay in reading all the records meant a match was not found and the fail command as specified by BT was actioned.
We have now corrected our services and hope this information helps others.