The triggering event may be an email bounce. I get a lot of github notifications sent to my email, and the failure of just one/a few may trigger the reverification.
When this happens, you can spin up a temporary server and have a mechanism in place to redirect email so you don't go down when your provider does.
Losing incoming email is pretty much the worst case scenario when it come to configuration errors. It about as bad as not having backups, in that both cases results in unrecoverable loss of data.
> When this happens, you can spin up a temporary server and have a mechanism in place to redirect email so you don't go down when your provider does.
Use a commercial provider, but fall back to your own server when it goes down without changing your email address.