Can’t Receive Messages & New Followers Get Warning – Ongoing Issue

Hi everyone,
I’ve been dealing with a strange issue for the past few months – people are unable to message my page at all (no message button), and when someone tries to follow me, they get a warning notification like “Be careful who you follow.”
I’ve checked everything I could on Facebook and Instagram settings, but nothing helps. Has anyone else experienced this? Any idea what might be causing it and how to fix it?
Thanks in advance!