Describe the bug, provide any errors
A clear and concise description of what the bug is. Can you https://paste.gg/ the error?

How can we reproduce it?
Steps to reproduce the behavior:

1. Have all viaversion plugins installed including this one ON PAPER 1.16.5
2. Login with 1.8
3. Error
4. (you should also see it on console)

Expected behaviour
A clear and concise description of what you expected to happen.
No errors and should be working correctly
Screenshots
If applicable, add screenshots to help explain your problem.

ViaVersion Dump:

• Type /viaversion dump, and put the link here.
  https://dump.viaversion.com/c7fced55c517f260b7ce52760fe09bf79e1c6979c008e5d9e5b4cd2b2b1ed345
  Additional server info
  Do you use a proxy (eg. BungeeCord)? What software do you use and what plugins?
  no
  Checklist (mark with [X] to check)
• I have included a ViaVersion dump
• If applicable, I have included a paste (not a screenshot) of the error
• I have tried a build from https://ci.viaversion.com/ and the issue still persists
• I have looked at https://www.spigotmc.org/resources/viarewind-legacy-support.52924/ and it does not offer a fix for my problem

IMPORTANT: Follow the Checklist or we can't reproduce your issue and your issue will be close

and what's the error?

Error message???

It looks like you don't have viaversion installed. It looks like you are using a third party plugin for compatibility.