I get error message 0781 when trying to send PC. I also get id or password incorrect if I try to send on my Ipad.
I am forwarding my BT emails to a Gmail account and this appears to work. I have spoken to Customer Services also, who had no idea and said they would pass it to the technical team. What are they then? I am waiting for a telephone call from them. I will try changing my password (which I have done several times recently). By the way, this happens with just one recipient of the email.