Currently, when a new user makes a meta question about their own post specifically, they are prompted to enter a link to their post, and then they are given access to the per-site meta's question asking form, where the body is prefilled with mandatory header text that contains a link to the post they're asking about and a note that questions not about one's post will be deleted.
When submitting the question, the system checks to see if that header text is still in place at the top, and if not, doesn't let the question through, and gives the following error message:
You must have a minimum of 5 reputation to post on this site.
Recently, we had a user who couldn't figure out what was going on when they, after putting in a link to their post in the first field and then typing up their question, were still prompted that they needed 5 reputation despite other help pages and users here telling them they could still post. Eventually, we figured out that the author had accidentally removed said header text when typing their question.
Later, the user tried again, but this time put their question above the added text, and still received the error message. It seemed to me that they were already getting pretty frustrated; thankfully, they still remained communicative enough to receive my message to put their question below the added text.
Overall, a user had a very frustrating experience that was caused by an improperly communicative error message. The whole experience could have been solved if the user more easily knew that it was because the header text was being removed or misplaced that they weren't allowed to post.
Can we make the error message on the question form, when a low-rep user attempts to submit a meta question where the header text has been removed or misplaced, be more informative about the actual issue? An example:
Please make sure that you haven't typed over or deleted the prefilled header with the link to your post. If necessary, please go back and fill in the form again.
I think this can be done by simply modifying the error text above, as that error is pretty much only shown if the user actually access the question asking form, which they can only do if they enter a link to their own post at a gatekeeper screen. A better fix would be to not insert the header text into the post body when the asker is typing their post, but instead insert it upon submission; this way, there's no risk of the author accidentally removing or typing over it and thus no such error will show, but that would probably be technically infeasible.