To change your servers difficulty, log into LYHMEPanel, select and stop your Unturned Server, then follow these steps:

1. Click on "Configuration Files

2. Click on [Text Editor] Across from Commands.dat  

3. the second row down, it will appear as the following.

PvP

4.
 Remove "PvP" This can be PvP or PvE

5. Once you are happy, click SAVE

6. Start your server