From Feudal Wiki
If you see console errors from Feudal follow this guide:
- Did the errors appear after changing something in the config? If so, do not report this, undo your changes and make sure you didn't add a decimal where an integer should go, make sure your config does not have ANY tabs (only spaces), and make sure you didn't put letters where numbers should go. Also do not remove configuration fields (they look like this "field: value").
- Is feudal up to date? Download the latest version here
- Is your server in 1.8 or later? If not, make sure to update your server.
- Did the errors appear after updating to the latest spigot version? If so, this means Feudal has yet to update to that version. Be patient.
- Did the errors appear after installing another plugin? If so, report this problem.
- Did your server crash? If so, don't report unless the crash was caused by Feudal.
- At this point you can report this problem.