Sendmail before and after upgrade to 13.1

From: <latincom_at_vcn.bc.ca>
Date: Mon, 13 Jun 2022 07:27:57 UTC
Hello

I have an web/mail server 13.1 it was working correctly, but after upgrade
to 13.1 my e-mail is considered spam! With 13.0 it did not happend!

Does anyone know what could happend?

Another question:
How to configure Sendmail with Let`s encrypt please, the installation of
certbot is failing: The message says that plugin is not working!

Thanks so much.