[Hosting - Plesk] Mail service disrupted

After a vendor update, sites on the Plesk Hosting service are not able to send outgoing mail via the sendmail/SMTP utility.

We are currently researching and testing the vendor's suggested fix-it steps before applying them to the service.

Thank you for your patience!

the fix-it steps aren't working (no change in behavior turning the mail service on and then off again for a domain). A ticket with the vendor is being opened.

The test of the vendor's suggested fix-it steps was unsuccessful.

We're going back to the vendor to ask them to dig into the issue and provide new steps.