Some months ago I was having increased problems with bt mail. Decided to move to icloud.com instead of btinternet.com for mail, so now 90% mail comes via iCloud and 10% to BT. For the past couple of days I cannot access the bt.com mail and keep getting a message 'cannot connect to account BT Internet. Enter password'.
I try the password I remember, but it does not work. Try a few old pwds but no luck. It does not offer me 'Forgot password' so I am stuck.
Maybe not related, but on 2 June I had to contact BT as my contract needed renewed, got a helpful guy who sorted that out and I told him about changing email but that I was afraid to change anything within BT in cased I messed it up. He said something like I need to keep the BT address for something central, but I could change email which means that if BT need to contact me they will use the new iCloud mail address. He offered to do that so I agreed (and dreamed I would never have any more problems with email ...ever).
So now when the error message asks me to enter password, I don't actually know what I am to enter. The message has already entered my btinternet.com account name and no option for me to change that. I did try to phone or live chat with BT but was referred to your goodselves. Sorry for the length of this but it is hard to explain in a few words.