Form stopped working after 6yrs – 5.7.1 Message rejected due to content policy (

Dear all,

I really (really) hope someone can help me with this issue.

I have been using CF7 & Post SMTP without any issues over the last 5 yrs.

Last Friday the contact form stopped working on all my 8 websites (all different domains/sites).

Post SMTP gave this message in the Log whenever someone tried to fill out the contact form:

“5.7.1 Message rejected due to content policy (e9bf52bd-f14a-11ec-b9ee-d0431ea8bb1d) SUI”

I contacted my hosting (one.com) about this and they told me the following:

“`Dear Nick,

Thank you for your patience.

I just got a reply from the technicians and it seems to be an ip address problem caused by a plugin you are using. The problem is due to the sender’s ip address, 2.1.1.1. This is currently listed with Spamhaus Zen and must be removed in order to deliver these emails: https://check.spamhaus.org/listed/?searchterm=2.1.1.1

If you have any further questions, please let me know.
I wish you a nice day.
Sincerely,
Arthur”

When I checked which plugin was causing this, they mentioned POST SMTP.

What could be causing this out of nowhere? I didn’t change any settings in POST SMTP or so. I have no clue in which direction to look.

I would love to keep on using POST SMTP. Hopefully someone can tell me in which direction to look to solve this issue.

Best and much appreciated,
Niek

The page I need help with: [log in to see the link]