This happens after a GTA V update. You must wait for Alexander Blade to update Script Hook V and then replace your old ScriptHookV.dll with the new one.
Assuming you mean whether Script Hook V + Native Trainer (version 1.0.8.771 or similar) still works and where to get it safely:
Script Hook V is the industry-standard library required to run custom .asi scripts and trainers in Grand Theft Auto V




