Problem with IA

I was working on my project and I realized that my AI did not move (with the IA move to)(a week ago my script worked well and now it does not move anymore). I try many ways to solve the problem but I find nothing : I have a refenrence plugged in my pawn pin (self) and my scripts are well written. I put print string in several places to see where it was the error but everything is good. I do not change unreal engine version. (I work in blueprint)
I can someone help me !