My websites have not been sending any email notifications out to people who had subscribed to page edits. The reason was that I had switched my Google account to use 2-step verification. Only today did I realize that the error messages were trying to tell me that I needed an application specific password for my script.
Everything should be back in working order.
I feel relieved. For a while I thought I’d have to dig around in the Perl SMTP libraries. Ugh!
And I feel much better with 2-step verification. The Mat Honan story was scary.