Computer Help and Support

I have sent and received multiple copies when the email server is lost in space.

Mail servers queue up outgoing and incoming emails, and when they have problems reaching destinations, they retry.

And you never know what was the hangup: Storage slow or down, like AWS (Amazon) or some hangup at Cloudflare or a nasty network outage at who knows where.

I keep two email accounts, and use various apps to handle mail, so at the very least, I can get a better handle on problems.

If Thunderbird works at all (as say it does) then it's probably configured correctly.