Minecraft 1.15.2
Waterfall : 326
Paper: 143
Marry version: https://pastebin.com/raw/Uys5hWYV

BungeeCord online mode!

Server/crash log from bungee console: https://pastebin.com/raw/ft8Ni9XQ

Please update to this build: https://ci.pcgamingfreaks.at/job/MarriageMaster/159/artifact/artifacts/MarriageMaster-2.1.4-RC2-Release.jar

Could you please provide me with the startup log.

I used the version MarriageMaster-2.1.4-RC2-Release.jar and it fixed the above problem but i am getting a new error now.

https://pastebin.com/raw/WrWSzACJ

Sure, here it is
latest.log

Should be fixed with this build: https://github.com/GeorgH93/MarriageMaster/releases/download/v2.1.4/MarriageMaster-2.1.4-Release.jar

Yeap that version fixed it, thanks.