F1 and F2 settings resetting - how to solve it?

Hi, my free trial has almost expired and I have one problem I cannot solve. I use the app only to have standard function keys (F1, F2, F3...) on my company's ERP app, without using fn key. After setting it works perfectly, but after restart, the F1 and F2 keys stops working as supposed and are functioning as before (brightness down and up). What wight be the reason? How can I fix it?