Spawn protection stops people who don't have permissions or who are not opped from damaging a small radius around the world spawn point. It can easily be changed or disabled to fit your needs.
To change or disable spawn protection:
Select the server you'd like to update spawn protection for in the panel.
Open the "File Manager" along the sidebara and edit the "server.properties" file.
Locate the option called spawn-protection and change the value to the number of blocks you would like to be protected (e.g. spawn-protection=20). Changing the value to 0 (spawn-protection=0) will completely disable the spawn protection.
Save the file and restart the server to apply the changes.