Character is falling down

I dont know if this is a bug or im just dumb,but the characters are falling down after 5 seconds, in these 5 seconds they can walk and jump how i wanted,but then they just fall trough the ground, am i doing something wrong?

You need to give a lot more information. What are your events? What behaviours have you added to the character? Does it happen if they just stand still, unmoved? Or only one you move? Does the character have animation frames? If so, do all the frames have a collision box defined?

The Characters are falling down too if they move and if they stand still, the behaviours are Health, Physics2 and Platformerobject, the events are: d key is pressed-add to character an insant force of -100 p/s on X axis and 0 p/s on Y axis, the same for f just not -100 but 100

Both behaviors are not compatible at the same time on the same object. This will always lead to various unresolvable conflicts.

What @jack wrote is correct. So you’ll either need to remove one of them, or turn one off and the other on using actions: