BT pop/smtp servers have been very erratic for several years at least. Worse in the past 6 months. I only use it for a couple of odd things and BT announcements, but find that the servers time out regularly.
I'm often abroad, I made the mistake of accessing the box from a foreign IP. Result- locked out until I returned to the UK. Then it was a rat run of dead links and non functioning reset pages to get back in when I returned.
As it's for business buy a good domain and email service, the difference is night and day.
BT Infinity 2, HG612, Billion 7800N; 79987/19999 Kbps. Online since 1987. Macs since 1979. Dreambox fun. Advanced Radio Amateur Licence and an anorak.