This happens every time BOTW gets an update, the addresses move around with every update, so the current code addresses in the trainer no longer work. You will have to wait for an updated trainer to be released, or until SkoolzOut releases his updated BOTW codes on his pastebin, to use in JGeckoU.
Or you can try to use the codes that I posted in a "txt" (text) file, the post is a few posts up, you just have to search this thread. The codes I posted are codes that
@skoolzout1 had on his pastebin before deleting them completely. He deleted them because the codes he created didn't work for everyone, I think they didn't work for the EU/PAL version of the game, or something like that. All I can say is to try them for yourself. They worked completely fine for me, and I am using the US/NTSC version of the game, with the latest Update (v1.3.0/v97).
They are not ALL the codes though, just most of the most important codes, such as Inf Health, Inf Stamina, Inf Arrows, etc... The Health and Stamina codes take your current amount of health and stamina and freezes the value (im pretty sure thats what it does), so no need to edit the code to match your current amount.
Also, for the Inf Arrows Code to work, you must press the D-Pad (I forget the exact direction on the D-Pad) to bring up the Arrows Quick Selection Menu at least once for the code to activate in-game.
If those codes don't work for you, you will need to wait for either Skoolzout to update his pastebin with his updated codes, or until PandaOnSmack updates his trainer.
Good Luck!!