[Solved] Collision between character and obstacle not working

Hello everyone, I am new to making a game and have a lot of trouble with collisions. The blue band is my obstacle that I try to use to define the limits of the screen. When I saw that nothing happens I tried to test by deleting the blue obstacle which would be an immediate confirmation that no collision is detected. And indeed, nothing happens when the character and obstacle overlap as you can see in the picture. I wonder if I defined them wrong, the obstacle is just a sprite with no behavior and the player is a sprite with a top down behavior. Thanks in advance for your help!

Are the obstacle and player object on the same layer?

Yes both seem to be in the base layer, when I hide it both disappear so I guess it confirms that

What are the collision masks for the player and obstacle objects? Do you create another obstacle object in any other event?

Thank you so much for your answer!! Indeed the player didn’t have a collision mask this is why it wasn’t working. Since I’m a beginner I never knew of something like this. Thank you very much for your help!