Before open an issue, checkout this steps:

The bug happends when you claim an area in the new 1.18 update. the bugs makes it so that the claim doesnt reach below y=0

Steps to reproduce the behavior:

1. claim a place
2. go below y=0
3. try using any command for the claim
4. See error

the server is in 1.18 and is a paper server

Go to config and look for configuration minY=0 and set the min value for your world. It already on latest dev builds.