Why can’t I send private messages after all this time?

Hi, I’ve used the feature to direct message people plenty of times before and all of a sudden I can’t message anyone. I understand it may be due to the individuals account restricting access to non-followers to messages but it’s pretty much every account I click on. I’ve done a theory to test and I just don’t believe that every single account I come across has enabled that restriction.

If anyone has had this happen before? Or is there something in my settings restricting me from messaging others?