java.lang.RuntimeException: Could not execute entrypoint stage 'main' due to errors, provided by 'viafabric-mc1214' at 'com.viaversion.fabric.mc1214.ViaFabric'!
at net.fabricmc.loader.impl.FabricLoaderImpl.lambda$invokeEntrypoints$2(FabricLoaderImpl.java:403) ~[fabric-loader-0.16.10.jar:?]
at net.fabricmc.loader.impl.util.ExceptionUtil.gatherExceptions(ExceptionUtil.java:33) ~[fabric-loader-0.16.10.jar:?]
at net.fabricmc.loader.impl.FabricLoaderImpl.invokeEntrypoints(FabricLoaderImpl.java:401) ~[fabric-loader-0.16.10.jar:?]
at net.fabricmc.loader.impl.game.minecraft.Hooks.startServer(Hooks.java:63) ~[fabric-loader-0.16.10.jar:?]
at knot/net.minecraft.server.Main.main(Main.java:113) [server-intermediary.jar:?]
at net.fabricmc.loader.impl.game.minecraft.MinecraftGameProvider.launch(MinecraftGameProvider.java:480) [fabric-loader-0.16.10.jar:?]
at net.fabricmc.loader.impl.launch.knot.Knot.launch(Knot.java:74) [fabric-loader-0.16.10.jar:?]
at net.fabricmc.loader.impl.launch.knot.KnotServer.main(KnotServer.java:23) [fabric-loader-0.16.10.jar:?]
at net.fabricmc.loader.impl.launch.server.FabricServerLauncher.main(FabricServerLauncher.java:69) [fabric-loader-0.16.10.jar:?]
at net.fabricmc.installer.ServerLauncher.main(ServerLauncher.java:69) [fabric-1.21.4.jar:1.0.1]
Caused by: java.lang.NoSuchMethodError: 'com.viaversion.viaversion.api.minecraft.entities.EntityTypes1_11$ObjectType com.viaversion.viaversion.api.minecraft.entities.EntityTypes1_11$ObjectType.findById(int)'
at knot/com.viaversion.viabackwards.protocol.v1_10to1_9_3.rewriter.EntityPacketRewriter1_10$1.register(EntityPacketRewriter1_10.java:59) ~[ViaBackwards-5.2.1.jar:?]
at knot/com.viaversion.viaversion.api.protocol.remapper.PacketHandlers.(PacketHandlers.java:38) ~[viaversion-5.2.2-SNAPSHOT-ca0328167a63bd3e.jar:?]
at knot/com.viaversion.viabackwards.protocol.v1_10to1_9_3.rewriter.EntityPacketRewriter1_10$1.(EntityPacketRewriter1_10.java:44) ~[ViaBackwards-5.2.1.jar:?]
at knot/com.viaversion.viabackwards.protocol.v1_10to1_9_3.rewriter.EntityPacketRewriter1_10.registerPackets(EntityPacketRewriter1_10.java:44) ~[ViaBackwards-5.2.1.jar:?]
at knot/com.viaversion.viaversion.api.rewriter.RewriterBase.register(RewriterBase.java:36) ~[viaversion-5.2.2-SNAPSHOT-ca0328167a63bd3e.jar:?]
at knot/com.viaversion.viabackwards.protocol.v1_10to1_9_3.Protocol1_10To1_9_3.registerPackets(Protocol1_10To1_9_3.java:56) ~[ViaBackwards-5.2.1.jar:?]
at knot/com.viaversion.viaversion.api.protocol.AbstractProtocol.initialize(AbstractProtocol.java:106) ~[viaversion-5.2.2-SNAPSHOT-ca0328167a63bd3e.jar:?]
at knot/com.viaversion.viaversion.protocol.ProtocolManagerImpl.registerProtocol(ProtocolManagerImpl.java:211) ~[viaversion-5.2.2-SNAPSHOT-ca0328167a63bd3e.jar:?]
at knot/com.viaversion.viaversion.protocol.ProtocolManagerImpl.registerProtocol(ProtocolManagerImpl.java:205) ~[viaversion-5.2.2-SNAPSHOT-ca0328167a63bd3e.jar:?]
at knot/com.viaversion.viabackwards.api.ViaBackwardsPlatform.init(ViaBackwardsPlatform.java:101) ~[ViaBackwards-5.2.1.jar:?]
at knot/com.viaversion.viabackwards.ViaFabricAddon.run(ViaFabricAddon.java:37) ~[ViaBackwards-5.2.1.jar:?]
at java.base/java.util.ArrayList.forEach(ArrayList.java:1596) ~[?:?]
at knot/com.viaversion.fabric.mc1214.ViaFabric.onInitialize(ViaFabric.java:94) ~[viafabric-mc1214-0.4.17+102-main-5375f3619c694112.jar:?]
at net.fabricmc.loader.impl.FabricLoaderImpl.invokeEntrypoints(FabricLoaderImpl.java:399) ~[fabric-loader-0.16.10.jar:?]
... 7 more

not with via

and also issue template was not followed.