Have you checked if a similar issue is already reported by someone else?

• I checked there are no similar issues have been reported.

Have you read the support policy?

• I read it and I accept the policy.

Are you using the latest Epic Fight and recommended Forge version?

• I checked I'm using latest Epic Fight and recommended Forge version.

Is this issue related to mod incompatibility?

• This is a mod compatibility issue and I'm aware of the problem.

The mod

https://www.curseforge.com/minecraft/mc-mods/epic-fight-mod

Minecraft Version

1.20.1

What happened?

I can't attack enemies on a slab in my xp farm . Same with trap door or cappet.

I guess you struck entities behind a wall or somewhere. Epic Fight doesn't allow striking the enemies behind a wall or out of the player's sight. Just recommend you use vanilla attacks.