Remote Server returned ‘550 5.7.520 Message blocked because it contains content identified as spam. AS(4810)’
Something in it appears to be spam. Possibly because of the subject and that it is being forwarded.
>> Content-Type: application/ms-tnef; name=”winmail.dat”
It appears you are sending this from outlook desktop and the message format is RTF. Sending as HTML might help.
If you are using outlook desktop software, see
If you are using outlook on the web, delete the address from the autocomplete list.
Outlook Resources: https://www.slipstick.com
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