TLS it not available or unauthenticated but required

[cbrake]

I've observed problems delivering email to several different people I communication with:

queue: delivery attempt failed  {"domain":"sbcglobal.net","msg_id":"45d30471","rcpt":"[email protected]","reason":"TLS it not available or unauthenticated but required","smtp_code":451,"smtp_enchcode":"5.4.0","smtp_msg":"No usable MXs, last err: TLS it not available or unauthenticated but required","target":"remote","tls_err":null,"tls_level":"none"}

Changing the following gets email delivered:

target.remote outbound_delivery.mx_auth.local_policy.min_tls_level = none

I don't like this, but the chances of getting everyone to fix their email servers is next to zero.

Can you confirm that Maddy does use TLS if it is available on the target server, even with this none setting?

[foxcpp]

Yes, TLS is always tried and DANE and MTA-STS are still used