mail not passing queue through Postfix SMTP

OpenCart v4.0.2.3
PHP v8.2.7

wether the setting is Mail or SMTP (both cases), when i use the Contact Us form, the message just sits in the message queue on my SMTP server.
i investigated, and the From and Subject field appear malformed from OpenCart. they start "=?UTF-8?" followed by some code. all other email passes my SMTP server so this is i think the stoppage, though i may be uninformed.

so the question is, what do i need to change in OpenCart?

if this is a Postfix issue, i am running v3.7.10, if somebody knows and can help me fix the processing of these messages.

Thanks in advance for any help :-)

it was an issue with my DKIM milter, fixed, and messages are now processing :-)

BTW, clicking the smilies above didn't work on my browser (Firefox 12.3.0.1 on Windowz 10). it just jumped the scroll and placed no smiley on message.