I have been using links found here
Mac OS X 10.10 Yosemite Postfix SASL authentication failed
as a workaround for a blocked port 25 on Comast, to route outgoing mail, generated by shell scripts, through Gmail's smtp servers.
As of a few days ago it stopped working, right after security update 2017-0001.
Notes on that say:
802.1X
Available for: macOS Sierra 10.12.6, OS X El Capitan 10.11.6
Impact: An attacker may be able to exploit weaknesses in TLS 1.0
Description: A protocol security issue was addressed by enabling TLS 1.1 and TLS 1.2.
Mail stays qued and says "(TLS is required, but our TLS engine is unavailable)"
Logs say:
default 01:30:44.880027 -0500 smtp warning: Digest algorithm "md5" not found
default 01:30:44.880077 -0500 smtp warning: disabling TLS support
standalone md5 is alive and working, as is openssl md5
The only mention of anything that might be related to this that I can find is at
https://teratail.com/questions/98920
at this point I feel a bit out of my depth
UPDATE: An upgrade to 10.13.1 seems to fix this as noted here
