Need to press the TAB key after inputting the new value and make sure the lock icon is not on.
Please delete the trainer, custom keys, debug folder where the trainer resides and all files in
Learn how to make your own Trainer Cleaner for the above paths here
Reboot PC to clear excess memory, get a fresh copy of latest trainer and extract it. Run trainer as admin, read the instructions and try again. At times, a new game may be needed to resolve failed options if the data in your save file was altered. Use on a new game and test the option. If it now works, quit to main menu and load your save and try it again. May also need to run the game without the trainer first and play a bit so the save file gets updated to use possible new values. This typically will resolve the issue.