Last weekend I had to verify a third party account via my Thunderbird email address. I tried six times and didn't receive an email. This was ridiculous. It had never happened previously. I double checked my back up Gmail account and the emails weren't there either which clearly demonstrated that I hadn't received them. I spoke to the company today who could only keep reiterating that they'd been sent and they could "see" they had been received. The fact that nothing appeared in my Gmail account either meant nothing and the fact that this had never happened with Thunderbird previously also meant nothing. I was told in no uncertain terms that the problem was at my end. The most annoying part is that for every other thing they use my Thunderbird email address without any problem so having been told that the problem was my end they had no answer as to why some emails arrived and some did not. I was asked to contact Support to see if for some reason they'd been blocked. Advice would be much appreciated.