Server errors: 'The following microblocks are not installed on this client' & disappearing block glitch

[Dude99710]

Whenever I try to start my server, I get the following message:

"The following microblocks are not installed on this client"

 

I only seem to get this message when starting the server with launch.bat, but when I use the server.jar, any mod blocks on the server disappear after placing them, and spawning mod entities stops the server. Terrain mods such as Biomes o' Plenty don't work either. Vanilla blocks still work normally though. A fix to this would be greatly appreciated.

[Kalbintion]

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