Here is a screenshot, containing the icon (the one in the middle, presumably describing a text note, with what looks as a stop sign at lower right corner of it):
I cannot find explanation on what is being communicated to me here? Most of the time the icon does not have the stop sign overlay there, but regardless of this, clicking on it simply gives me the Action Center pane that says "No new notifications".
So, what could that overlay indicate? I am not the worrying type, but I am an IT specialist, so I want to know what's going on.