When I want to edit one of my messages on THIS website, in the role of a normal user, I get an exception. So I cannot do corrections to messages.

(I want to emphasise, that there are no such errors on my own websites with YAF 3.1.13, where editing works properly.)

Test EDIT message...

Does the error message appears when you load the page?

Can you post the error message?

I get the error, when trying to update messages on this YAF website. (I had a similar error a few days ago on another message).

This one is from a minute ago on the first message in this thread, saved with EDGE, and appended ".TXT" for upload as attachemnt:
 Obj_not_set_Error500.html.txt You have insufficient rights to see the content.

(The exception error appears as a response to saving the edited message.)

A posteriori test.
UPDATE: Yes, it works now! 
 

issue should be fixed now