Server Error while loading

I have this consistent problem with loading my forge server that I created with my friend and no matter what we do, the server always comes up with the message similar to , payload may not be larger than 1048576 bytes. We are both unsure of what to do and cant fix this problem

Quote from Powerful845tiger

Try using https://www.curseforge.com/minecraft/mc-mods/xl-packets on your PCs

I have XLPackets within this mod pack