It worked, now it doesn't. It just pops up the error "You aren't logged in or the authentication data cannot be retrieved." Yes, I did try the given solutions, switching FB to classic view did nothing. Any help?

I changed the FB view bt it doesn't work at all.

i am 100% sure that it gives incorrect results

Edit : 1 of my friend's conversation count was more than 150000 about an year ago , when Facebook used to show text "loading xxx messages" when scrolled towards top . Your addon is still showing the same number after more than a year. So there's definitely something wrong here