Is there an issue with Settings > SMTP > Outbound > DNS > Quad9 (TLS)? I get DNS resolution error: proto error: io error: connection refused)

[rcfa]

Is there an issue with Settings > SMTP > Outbound > DNS > Quad9 (TLS)?
I get delayed/unsent messages, with the mail system sending me delay reports complaining about:

There was a temporary problem delivering your message to the following recipients:

<[email protected]> (failed to lookup 'host.domain.tld': DNS resolution error: proto error: io error: connection refused)
Reporting-MTA: dns;mail.myDomain.tld
Arrival-Date: Thu, 1 Mar 2025 18:51:31 +0000

Final-Recipient: rfc822;[email protected]
Action: delayed
Status: 4.0.0
Will-Retry-Until: Tue, 6 Mar 2025 18:51:31 +0000

This is when I have selected Quad9 (TLS) as DNS server. I now switched to Quad9 (minus the TLS part).

To be seen if the issue persists… Anyone else seen something like that?