@dunlix understood. I think that this error is caused by OSCP stapling - see https://support.mozilla.org/en-US/questions/1149911
Solved Customizing error alerts (Pop ups)
I'm looking for a way to customize the error alerts which pop up down in the corner.
Example given the error alert which appears when someone without the privilege clicks on the chat icon.
Could anyone help me?
For example: I don't want the user to get the notification in the right corner saying "error: you don't have the rights for this action" when he's trying to use a function he just can't use yet.
Instead, I'd like him to get a notification which tells him that he can't use the certain function yet but is going to be as soon as he has more reputation/more posts/etc.; this would be a way of activating some users more
@PitaJ That's it! Thank you very much