Is there an error message?

This was the message I got -- I've just deleted the addressee's name:

Reporting-MTA: dns; avasout-peh-002 [212.159.14.18] Received-From-MTA: dns; [192.168.1.67] [146.199.87.140] Arrival-Date: Wed, 14 Jun 2023 10:30:09 +0100

Final-recipient: rfc822; ***@gmail.com Diagnostic-Code: smtp; 550-5.7.26 This mail is unauthenticated, which poses a security risk to the

Last-attempt-Date: Wed, 14 Jun 2023 10:30:09 +0100

Gmail has tightened security recently and giving you a code 550. There are various possibilities, such as sending from an SMTP server with account xxx but the email return address is yyy. I cannot say what is causing your error, but it's worth review. Check your smtp settings and authentication.