Why uw.edu not accepted my signed email?

[Claus Assmann]

On Tue, Nov 16, 2021, Andrew D. Arenson wrote:

>       I don't see any obvious configurations that set how email is
>       sent, so my guess is that it is being send via sendmail on my
>       Ubuntu workstation.

Then you should be able to check the maillog(?) for those
TLS problems and also check the mail queue:
mailq

Also check the DSN again: does it say which is the "reporting MTA"?
That's most likely the one which has the TLS problem with uw.edu.