How do I keep my TicTac tiles from popping up?

If you are looking for permanent placement, try Loctite's Power Grab. You will probably have to use painter's tape to hold in place until it dries completely.

What is underneath the tic tac tiles? Maybe there's something there that they can't stick to well - like a greasy or dusty or very smooth wall? It depends on what that is for how you fix it. :)

I would look into the gorilla glues :)

Excess moisture may be contributing to your problem, also it depends on what they are stuck to. If the surface is irregular, like stucco, they may not stick well, too many gaps, they need a flat surface.

Did you wash your walls with TSP to get rid of any grease, residue, and to give a clean surface to start on?

You’ll do this step even if you didn’t have to sand your walls. Allow your walls to fully dry.

A little construction adhesive will help keep the corners down

Hello. Do you have a reason that the tiles might not be sticking to cause this failure? Was your surface clean and smooth?

A gorilla glue or a construction adhesive might be an option to consider. The construction adhesive can be purchased in large Caulk type packaging tubes as well as smaller toothpaste type packaging depending upon the projects surface area you need to repair.

most of the info I found says to use extra adhesive if you use in a kitchen because of the heat and steam from stove and oven here is info https://www.youtube.com/watch?v=HsJTqCXDgHo