User automatically unsubscribed (DO NOT CONTACT)

Hey, I run Mautic v3.31, and I tried sending out some abandoned cart emails, to myself (an account), and immediately received the “DO NOT CONTACT” flag, as if I unsubscribed, but obviously, I didn’t do so.

I’m beginning to suspect it is an thing? Is there some way I can check and verify this?

I use Send In Blue as a SMTP relay, so it should be pretty reputable. SPF/DKIM, DMARC all set up properly too.

EDIT: The same also goes with And there is no way to remove this flag from Mautic’s site, unless I delete the contact and re-add it. And then it somehow does not trigger this the second time, sometimes.

There might be an error with your sending method.
You should check if emails are at all getting out. Mautic might just render all email as undeliverable.
When you send a test email - does it work?