Why does my watch faces delete from GARMIN/APP ?

Hello,

I need a little help please I'm completely new to development

I wanted to make a custom display for my watch, I simply want it to display a number that multiplies by 1.0005 every seconde

I think I succeeded in doing what I want, the code works on the PC, it launches without problem I also think I succeeded in compiling it, I had a BUILD COMPLETED and I have a .prg file

The problem is that when I connect my watch via USB and place the file on it, it does not appear on my watch and the next time I connect the USB, the file is automatically deleted.

Would you know how to find the problem please?