client with Forge 47.3.0 and only Patchouli + ForestryCE cant connect to server, throwing constantly one error without any information, what caused it:
Internal Exception: io.netty.handler.codec.EncoderException: java.lang.NullPointerException: Cannot invoke "net.minecraft.world.item.ItemStack.m_41619_()" because "p_130056_" is null

tried with 2.0.0 and 2.0.1 versions.

Logs

Client:
latest.log
debug.log

Server:
latest.log
debug.log

I get exactly the same message on my update testing pack, but does work in solo

Client log:
latest.log

Server:
debug.log
latest.log