Nice touch from @fastmail. Several of my setups just exploded because they finally shut down a few of their deprecated domain names.
I got an automated email from them asking whether I needed help setting up my mail clients, after they persisted in using old domain names / passwords.
What I needed was to pay more attention to their deprecation warnings 馃槣 But the detection of the problem, and automated offering of help, was a nice touch and appreciated 馃挅