Thunderbird on my iMac has never had an issue with my Yahoo! mail account. I've been using the Yahoo two-step verification method without a hitch. Today, Thunderbird threw me timeout errors and asked for a new password for my Yahoo! account. I created a new 2-step app password via Yahoo!, but the errors kept coming. So, I removed the account from Thunderbird and recreated it. I can't get past the "Checking Password ..." prompt. For some reason, Thunderbird either is not accepting the 2-step app password or the Yahoo! email account password. I've also tried changing my Yahoo! account password twice with no luck. Any advice? Should I remove a Thunderbird preference to start fresh? Not sure what to do. :/