The zombies that spawn in my fifth zone do not seem to be able to move and those spawning in other spawns can not get in. The zombies stuck in front of the door.

If you have zone A and zone B

If zone A is not connected to zone B the zombies in zone B won't move anywhere.
If there is any kind of gap between clips or blocks the zombies won't be able to path through. (ex. Each piece of stair needs to be connected. If they aren't connected but you can still physically walk over them just fine the zombie pathing won't work.)

So you need to find a way to get them through the doorway. Maybe it isn't wide enough, maybe the door way is too thick. Or not tall enough.

Thanks for the answer but it was the ground texture the problem.