Why is my skeleton farm not working (Minecraft)?

Have a skeleton farm everything is normal. But skeletons have not spawned for a few days. I wanted to know if someone could tell me.

Maybe you have too much light there or something.

It would be helpful to take screenshots or something similar, as magicced01 has already said.

Difficulty?

Perhaps you have exceeded the limit of max. 50 blocks from when chips are no longer monsters

But you can fix that: https://minecraft.tools/de/spawn.php