From what my friend told me, he was playing normally on the server, it was on the enderdragon to revive and kill him, he came back and made the draconic reactor and while he was making the draconic armor, the server just shut down. Okay, he went there and started the server again, but it always reaches the end, the server gives the status of online and seconds later it crashes.
This is the crash log, I’m using a modpack modified by myself, it may be that there is a mod in conflict, I don’t know.
java.lang.ClassCastException: blusunrize.immersiveengineering.common.blocks.metal.TileEntityFluidPump cannot be cast to cofh.thermaldynamics.duct.tiles.TileGrid
at cofh.thermaldynamics.block.BlockDuct.func_180656_a(BlockDuct.java:264
The issue seems to be an issue with Thermal Dynamics where it is attempting to use a Immersive Engineering Fluid Pump as a Tile Grid.
Sadly im not much more help then that. I would say report it to Thermal Dynamics but they have closed the issue tracker thanks to too many people reporting “user errors” and crashes caused by “mod packs”.