So I use Firefox (currently Quantum 62.0) and I also use the Grammarly addon for my facebook posts etc. It also worked here in the Petri forum but not any more.
Up until several versions back (pre-Quantum I think so probably version 56 or some such) Grammarly worked AOK but then just stopped. I’ve disabled several addons to see if that impacts it but it makes no difference.
My research led me to the following page on the Grammarly support site: