Hello and welcome to the community! 
The main reason why trainers suddenly stop working is due to interference from security programs on the computer or network, even if they were completely fine with them before. Please follow the steps in this thread here: "Wemod failed loading the cheats into your game" / "We’re having trouble downloading the cheats" - #2 by Ravenfyre.
If there’s no change, which games are you trying to play and which store did you buy them from (if you did 
)?