Steps to reproduce the issue

In Global Configuration - System you set up the SMTP email as the email type along with the server name, port, TLS email address, username & password. You then Press the test email button at the bottom of the form.

I found that you it looked better to set the SMTP email settings then <Save& Close> and then come back into the Global Configuration server settings and then press the test button to have an expected result.

Once SMTP is fully setup with a Expected results test, if you go into the Contacts form and attempt to send an email to one of the contracts, it again comes up with either of the Expected or Actual result error.

Expected result

You get a green bar along the top of the screen stating:
"The email was sent to {email address}using SMTP. You should check that you've received the test email."

Is you send an email with the Contacts option it should give "Thank you for your email."

Actual result

get an intermittent error message with SMTP 221 error of the form
"The following From address failed: {as set in server global config} : MAIL FROM command failed,{domain} Service closing transmission channel ,221,SMTP server error: MAIL FROM command failed Detail: {domain} Service closing transmission channel SMTP code: 221"

System information (as much as possible)

Joomla v4.4.3
PHP 8.2
My SQL 5.7 (yes its just out of support) but hosting does not yet support anything newer :(
Swapped from PHPmailer to SMTP so the emails are Authorised to match DMARC processing.
It looks like the services is just stuffing text into the buffer and the FROM: smtp address is read incorrectly. I have not checked the code as I am no fluent in PHP.

Additional comments

This looks to be intermittent in both the global configuration server setup test SMTP and also on the function in the main web site. The same error is happening 50% is of the time....