Hi,
Speaking with BT is challenging, at best. The problem was that some of their DNS resolvers looked like they had problems during a refresh period (where they fetch new records). This appeared to have corrected itself when their next refresh happened.
As they have multiple resolvers, some people had a problem and some didn't.
Can you confirm this is now fully resolved for you? Unfortunately for problems like this we have little control over how BT react. If it was a network routing issue we can speak to some helpful guys, but for something like this, it is very difficult to get them to even admit to a problem.
Kind Regards,
John - Managing Director