Server and single player works perfectly but whenever a player joins, the server crashes

Hi, just like in the title i do not understand why the server crashes whenever a player joins.

I cannot find a lot of information on internet about this but this is the error I get :

java.lang.NoClassDefFoundError: net/fabricmc/fabric/impl/networking/payload/PacketByteBufPayload

Caused by: java.lang.ClassNotFoundException: net.fabricmc.fabric.impl.networking.payload.PacketByteBufPayload

If anyone knows what this really means that would be amazing, trying to get the "Friends and foes" mod to work has proved challenging.

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This is the full crash report : https://pastebin.com/k4EFpCvY

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Thanks a lot for anyone willing to help, i've tried a lot of things and none of them works.