Character Movement Glitch - "Gliding"

So I was building a level today, without any issues, and suddenly my character won’t move correctly. I jump into the map and, only moving the camera with the mouse, my character unintendedly slides to one side of the map. I try using the WASD keys to move against the sliding, but with no success. Sometimes the sliding stops and the controls work fine for a while and then go crazy again. I’ve added a video showing what happens.

Is the Collision of the Environment properly set up? To me it looks like the Collision wants to be resolved.


Probably not as I’m a newbie to game development in general. I left everything at their default settings when i add them to the map.

I found out the issue. It seems that the window meshes were the culprit and, after deleting the windows altogether, the map works fine.