Exactly the same problem for me, only I’m on xBox. I too purchased the SoFly WPP but haven’t been able to use it for ages, it’s live weather only. Tried everything setting wise I think to no avail 
The only way I got it to work again was to get xBox live for a few hours and it came back to life, but I don’t want xBox live and shouldn’t have to have it
I don’t appear to have an “all players” option in “flight conditions”, maybe that’s just a PC thing 