How to Fix a Spawn Point That Puts Players Underground or in the Air
Why Bad Spawns Happen
Most spawn problems come from a manually set yCoordSpawnPoint. If the Y value is below the terrain, players appear buried in stone or dirt. If it is too high, they fall before the chunk finishes loading.
The Simple Fix: Let Y Auto-Select
Set yCoordSpawnPoint back to its default value of -1. In this mode the mod scans the X/Z column and places the spawn on the first solid block it finds, which almost always produces a valid surface spawn. Save the config and generate a new world to test.
If You Must Set Y Manually
Stand at your intended spot in-game and read the Y value from the debug screen. Use that number, or add one or two blocks of headroom so the player is not clipped into the ground. Make sure the block below is solid — spawning over water, lava, or a cave opening will drop the player.
Checking X and Z Too
A correct Y will not help if X or Z point at an ocean or a cliff face. Confirm all three coordinates match a spot you have actually stood on. After any change, always create a fresh world to verify, since existing worlds will not pick up the new values.