Problem MONSTER "ID 355 is Mismatched"

[realemotionx]

switched modpacks myself to FTB MONSTER because it has more interesting world gen with Highlands

when I try getting my game on my PC to connect to the server it throws this error

"ID355 is mismatched between world and game"

and I cant connect. Any help?

 

[buggirlexpres]

Are you switching both your client and server to the same modpack, same version, and not adding/removing any mods?

 

[realemotionx]

Fresh download of modpack at Client and fresh install of server on the server end. No Mods modified. Just click Launch and then try to log onto the server.