This is an perpetual issue with BT Connect email. One that NEVER EVER seems to get fixed. Nor does it seem to be any kind of priority.
I send messages to myself that don't even arrive.
Clients send me message that don't arrive, though they think there's no problem because they get no notification of a failure. This makes my clients think it is me that is disorganised and useless, when in fact it is BT.
I have spoken to BT about this on several occasions and I have been told that they are not going to fix it and in fact the lack of reliability IS a reason you can give to cancel your account with them and they have said that they would honour you breaking your contract with them for this reason. I urge you to reconsider your email provider as the lack of reliability and constant blacklisting of BTs servers reflects very badly on your business.
This week alone there have been at least 12 emails that haven't arrived. BT's response? "we need to see the headers" Well how do we send you headers of emails that we don't and CAN NOT receive ourselves?
An utter disgrace of a service.
You should allow people to configure whether the dodgy Microsoft Message filter that you employ is enabled or not. I'd rather receive all the spam in the world and filter it manually than lose valuable business communications (and clients).
The joke is that the domestic home user email is vastly superior to the paid-for 'business' email. On the home user service you have a range of useful configuration tools. There are none on the BT Connect product.
Also, the webmail is utter utter junk.