Sprites move into opposing direction of camera,

I am currently following a course in creating a 2D game. It worked fine, but suddenly the enemy sprites are moving into the opposite direction of the player.

For example, if I jump and the camera follows the player upwards, the enemies move down and sink through the ground.

I have tried to make the camera a child of the player for achieving camera following, and I have tried Cinemachine and it happens with both configurations.

Is this any setting that I am unaware of and that I changed by accident?,

I just figured out after I encountered the same problem:

In the camera settings check if Projection is set to Perspective. If so, change it to Orthographic.

For me this solved the issue. If you have multiple cameras (like CinemachineVirtualCamera) be sure to check it in the settings off all cameras.