A) Why is this problem something that didn’t exist before but does now, and how do i find out what that problem is. and
b) Why does that problem only affect smtp and not the site as a whole? My SSL certificates are valid until april 2020, and https is working fine on the site as a whole…
Is there any method to troubleshoot why discourse suddenly doesn’t like my ssl certificates for smtp?
The SMTP you are using provides a DH key that is too small. Are you using your own SMTP server? If so, you are in good company. Rackspace had the same problem up until recently.