Firefox now refuses to load sites offering less than TLS 1.3 – at times you may need to allow this for a particular site to load/testing/etc.
However how do you re-enable for the warnings? Type :
into the address bar and then search for “TLS”
You’ll find this entry :
Change it from true to false (in the version used at the time of this post you could click the icon on the right side of the screen to flip the value from true to false).