Problem/Bug NuVotifier error

I am getting this error when using NuVotifier on certain websites. It works perfectly fine on PlanetMinecraft and MinecraftMP but on websites like MinecraftServers.org I am getting this error whenever someone is voting. I am using the correct key. I've also seen that people in the M.O.S.S Discord server are experiencing the same issue but no one seem to have found a solution. Does anyone here know what the issue could be?

https://pastebin.com/6C5C7QSN