Updated FF Tuesday evening and noticed first on Wednesday when unable to log in to my Tesco food website. Access not allowed from this server or some such. I tried to use the Tesco feedback form and then got alerts both from Avast (saying it was infected) followed by FF refusal to connect. I tried safe mode and removing and adding FF.exe to Avast without change. I reset FF without change. MS Edge allowed access to all these sites without a murmur. Today i can get to Tesco main site but still not Feedback. Also my local Synolgy NAS now has a warning that it is dangerous to access from FF. Nothing has been changed in its set up or security. I can and do override and access everything Something in the Tuesday update has caused this clash. I did think at one point I also saw 120.0.1 being offered but that may have been my confusion. Happy user of FF fro many years and do not want to change.