First I had to fix the crashes with client side only mods (so i removed few), but now this appered. I made around 4 modded servers but this is first time Ive seen this issue. The server looks to run fine, bu when I am trying to join this message appear Please help.
Forge Mod Loader detected missing/unkown registries
There are 1 missing registries in this save.
if you continue the missing registries will get removed.
This may cause issues, it is advised that you create a world backup before continuing
Missing Registries:
minecraft:dataserializers