How to reset Nether:
Summary: Delete the DIM-1 folder in your world folder.
[VANILLA SERVER]
1) STOP Server
2) Go to FILE MANAGER
3) Go to your world folder (if your world name is highfive, then look for a folder name called highfive and go in that)
4) Delete the DIM-1 folder
5) Start Server
[SPIGOT/BUKKIT SERVER]
1) STOP Server
2) Go to FILE MANAGER
3) Look for the world_nether folder (if your world name is highfive, then look for a folder name called highfive_nether and go in that)
4) Delete the DIM-1 folder located inside the world_nether or just delete the whole world_nether folder
5) Start Server
How to Reset The End:
Summary: Delete the DIM1 folder in your world folder.
[VANILLA SERVER]
1) STOP Server
2) Go to FILE MANAGER
3) Go to your world folder (if your world name is highfive, then look for a folder name called highfive and go in that)
4) Delete the DIM1 folder
5) Start Server
[SPIGOT/BUKKIT SERVER]
1) STOP Server
2) Go to FILE MANAGER
3) Look for the world_the_end folder (if your world name is highfive, then look for a folder name called highfive_the_end and go in that)
4) Delete the DIM1 folder located inside the world_the_end or just delete the whole world_the_end folder
5) Start Server