addForce and rotation problem in c++ HELP

Hello everyone! I trying to use addForce for my simulator. But I have one problem: my Character model rotate in scene when I start game. This happens when I turn on physics in blueprint class of Character. But if I turn off it, I can’t use AddForce. Can you help me solve this problem? And if you have tips, please, make them in c++, not blueprint. Maybe problem in 3d model or colllision with terrain?