I have had this response to my open ticket. He first copied and pasted this information:
"2020-05-08 17:23:50 Auth methods available on the server: DIGEST-MD5,CRAM-MD5,PLAIN,LOGIN
2020-05-08 17:23:50 Requested auth method not available:
2020-05-08 17:23:50 Auth method selected: CRAM-MD5
2020-05-08 17:23:50 CLIENT -> SERVER: AUTH CRAM-MD5 "
This is wrong, we don't support CRAM-MD5, so I am not sure why its showing that and attempting to connect to that. I just checked this from my end, and I can see that we don't list it:
220 smtp.fastmail.com ESMTP ready
250-AUTH PLAIN LOGIN
250 AUTH=PLAIN LOGIN
As you can see, we only support PLAIN LOGIN. So using AUTH LOGIN should work instead of AUTH CRAM-MD5.
As I said, I was afraid this is what would start happening.
I have already resonded with the message in the p;rivate area, and also them that we use "authenticated smtp", and that we do not know why his service is choosing to cycle through them in the way it does.
If you have any further comment to make, I will be happy to forward it.