Mailbox unavailable. The server response was: 5.7.1 rejected as Spam 2 4153

Hello, I tried to send an email invoice just now and the following message came back
Mailbox unavailable. The server response was: 5.7.1 rejected as Spam 2 4153

I then tried to send the email to myself and it has came back undeliverable
I tested the email settings and the test message was successfully sent
I searched the forum with a cut and paste of the information, but there was no current topic.
I checked with Microsoft and could only find information on spam due to filtering

Forgot to mention I am using the latest desktop version

This error is from SMTP server that you use. There is nothing that can be done in Manager to resolve this. You need to reach out to whoever is operating that SMTP server to give you solution.

Okey dokey, thanks for the quick reply as well
Kind regards
Doug