I started my server and it crashed immediately.

Log:
[10:51:19] [main/INFO]: Loading for game Minecraft 1.15.2
[10:51:23] [main/WARN]: Warnings were found!

• Conflicting versions found for fabric-resource-loader-v0: used 0.1.10+06c939b395, also found 0.1.10+06c939b30c
• Conflicting versions found for fabric-item-groups-v0: used 0.1.6+ec40b2e10c, also found 0.1.6+045efb460c
• Conflicting versions found for fabric-climbable-api-v1: used 1.0.0+e40501d40c, also found 1.0.0+6ffe71e20c
  [10:51:23] [main/WARN]: Mod everythingisahat (1.0.4) uses 'requires' key in fabric.mod.json, which is not supported - use 'depends'
  [10:51:23] [main/WARN]: Mod spelunkers (1.0.0) uses 'requires' key in fabric.mod.json, which is not supported - use 'depends'
  [10:51:23] [main/WARN]: Mod clear-skies (1.1.19) uses 'requires' key in fabric.mod.json, which is not supported - use 'depends'
  [10:51:23] [main/WARN]: Mod biom4st3rportal (2.0.1) uses 'requires' key in fabric.mod.json, which is not supported - use 'depends'
  [10:51:23] [main/WARN]: Mod armordisguise (1.0.2) uses 'requires' key in fabric.mod.json, which is not supported - use 'depends'
  [10:51:23] [main/WARN]: Mod betterdroppeditems (1.0.1) uses 'requires' key in fabric.mod.json, which is not supported - use 'depends'
  [10:51:23] [main/INFO]: [FabricLoader] Loading 173 mods: [email protected]+dfdb52d60c, [email protected], [email protected], [email protected]+1.15.1, [email protected], [email protected], [email protected]+build.198, [email protected], [email protected], [email protected]+build.1, [email protected]+1.15.2, [email protected], [email protected], [email protected]+2ad156310c, [email protected]+b7f9825d0c, [email protected], [email protected], [email protected], [email protected], [email protected], [email protected], [email protected], [email protected], [email protected]+mc1.15.2, [email protected], [email protected]+c6a8ea890c, [email protected]+mc1.15.2, [email protected], [email protected], [email protected], [email protected], [email protected]+1.15.1, [email protected], [email protected]+build.301-1.15, [email protected], [email protected]+003643510c, [email protected], [email protected], [email protected], [email protected], [email protected], [email protected], [email protected]+1.15.2, [email protected], [email protected]+mc1.15.2, [email protected]+build.32, [email protected]+mc1.15.2, [email protected], [email protected], [email protected], [email protected]+build.6, [email protected], [email protected]+3e5587510c, [email protected], [email protected], [email protected]+1.15.2, [email protected]+3b05f68e0c, [email protected], [email protected]+fac69e320c, [email protected]+b7f9825d0c, [email protected], [email protected]+build.1, [email protected], [email protected], [email protected], [email protected]+1.15-pre5, [email protected]+06c939b395, [email protected]+arne.6, [email protected], [email protected], [email protected], [email protected], [email protected], [email protected], [email protected], [email protected], [email protected], [email protected]+2e0c4ff50c, [email protected]+f3d8141b0c, [email protected], [email protected], [email protected]+ec951ea40c, [email protected], [email protected], [email protected]+dfdb52d60c, [email protected]+ec40b2e10c, [email protected], [email protected], [email protected], [email protected]+f08b61330c, [email protected]+1.15.2, [email protected], [email protected], [email protected], [email protected], [email protected], [email protected], [email protected], [email protected], [email protected]+b7f9825d0c, [email protected], [email protected]+3e5587510c, [email protected], [email protected]+b7f9825d0c, [email protected], [email protected], [email protected], [email protected]+821cdba70c, [email protected], [email protected], [email protected], [email protected], [email protected], [email protected]+12515ed90c, [email protected], [email protected], [email protected], [email protected], [email protected]+1.15, [email protected], [email protected], [email protected]+5a0f9a600c, [email protected]+e08a73050c, [email protected], [email protected], [email protected]+ad2f81bd0c, [email protected], [email protected]+1.15, [email protected], [email protected], [email protected]+e08a73050c, [email protected], [email protected], [email protected]+j1.2.0, [email protected], [email protected], [email protected]+2aebb7ff0c, [email protected], [email protected], [email protected], [email protected], [email protected], [email protected]+9290e2ed0c, [email protected]+fabric-20w06a, [email protected], [email protected], [email protected], [email protected], [email protected], [email protected], [email protected], [email protected], [email protected]+534104900c, [email protected], [email protected]+2a034f0a0c, [email protected], [email protected], [email protected], [email protected]+b7f9825d0c, [email protected], [email protected]+abd915800c, blue_endless_jankson@+, [email protected], [email protected], [email protected], [email protected], [email protected]+e40501d40c, [email protected]+1.15, [email protected]+003643510c, [email protected], [email protected], [email protected]+3e5587510c, presencefootsteps@r24+1.15.2
  [10:51:23] [main/WARN]: Mod berrysmod (1.2.0.1) uses more dot-separated version components than SemVer allows; support for this is currently not guaranteed.
  [10:51:23] [main/WARN]: Mod kayak (0.1.1.22) uses more dot-separated version components than SemVer allows; support for this is currently not guaranteed.
  [10:51:23] [main/WARN]: Mod immersivelighting (2.0.1F) does not respect SemVer - comparison support is limited.
  [10:51:23] [main/WARN]: Mod blue_endless_jankson (+) does not respect SemVer - comparison support is limited.
  [10:51:23] [main/INFO]: SpongePowered MIXIN Subsystem Version=0.8 Source=file:/E:/Minecraft%20Servers/FUCKS%20beta%20Server/fabric-server-launch.jar Service=Knot/Fabric Env=SERVER
  [10:51:27] [main/WARN]: Error loading class: net/minecraft/class_1132 (java.lang.ClassNotFoundException: net/minecraft/class_1132)
  [10:51:27] [main/WARN]: @mixin target net.minecraft.class_1132 was not found notenoughcrashes.mixins.json:MixinIntegratedServer
  [10:51:27] [main/WARN]: Error loading class: net/minecraft/class_634 (java.lang.ClassNotFoundException: net/minecraft/class_634)
  [10:51:27] [main/WARN]: @mixin target net.minecraft.class_634 was not found me.andre111.mambience.fabric.mixin.json:MixinClientPlayNetworkHandler
  [10:51:27] [main/WARN]: Error loading class: net/minecraft/class_3799 (java.lang.ClassNotFoundException: net/minecraft/class_3799)
  [10:51:27] [main/WARN]: @mixin target net.minecraft.class_3799 was not found me.andre111.mambience.fabric.mixin.json:MixinMinecraftClientGame
  [10:51:27] [main/FATAL]: Mixin prepare failed preparing BuiltinModelItemRendererMixin in sandwichable.mixins.json: org.spongepowered.asm.mixin.transformer.throwables.InvalidMixinException Cannot load class io.github.foundationgames.sandwichable.mixin.BuiltinModelItemRendererMixin in environment type SERVER
  org.spongepowered.asm.mixin.transformer.throwables.InvalidMixinException: Cannot load class io.github.foundationgames.sandwichable.mixin.BuiltinModelItemRendererMixin in environment type SERVER
  at org.spongepowered.asm.mixin.transformer.MixinInfo.(MixinInfo.java:855) ~[fabric-server-launch.jar:?]
  at org.spongepowered.asm.mixin.transformer.MixinConfig.prepareMixins(MixinConfig.java:715) ~[fabric-server-launch.jar:?]
  at org.spongepowered.asm.mixin.transformer.MixinConfig.prepare(MixinConfig.java:648) ~[fabric-server-launch.jar:?]
  at org.spongepowered.asm.mixin.transformer.MixinProcessor.prepareConfigs(MixinProcessor.java:515) [fabric-server-launch.jar:?]
  at org.spongepowered.asm.mixin.transformer.MixinProcessor.select(MixinProcessor.java:440) [fabric-server-launch.jar:?]
  at org.spongepowered.asm.mixin.transformer.MixinProcessor.checkSelect(MixinProcessor.java:416) [fabric-server-launch.jar:?]
  at org.spongepowered.asm.mixin.transformer.MixinProcessor.applyMixins(MixinProcessor.java:285) [fabric-server-launch.jar:?]
  at org.spongepowered.asm.mixin.transformer.MixinTransformer.transformClass(MixinTransformer.java:191) [fabric-server-launch.jar:?]
  at org.spongepowered.asm.mixin.transformer.MixinTransformer.transformClassBytes(MixinTransformer.java:178) [fabric-server-launch.jar:?]
  at org.spongepowered.asm.mixin.transformer.FabricMixinTransformerProxy.transformClassBytes(FabricMixinTransformerProxy.java:23) [fabric-server-launch.jar:?]
  at net.fabricmc.loader.launch.knot.KnotClassDelegate.getPostMixinClassByteArray(KnotClassDelegate.java:157) [fabric-server-launch.jar:?]
  at net.fabricmc.loader.launch.knot.KnotClassLoader.loadClass(KnotClassLoader.java:143) [fabric-server-launch.jar:?]
  at java.lang.ClassLoader.loadClass(ClassLoader.java:351) [?:1.8.0_232]
  at net.fabricmc.loader.game.MinecraftGameProvider.launch(MinecraftGameProvider.java:190) [fabric-server-launch.jar:?]
  at net.fabricmc.loader.launch.knot.Knot.init(Knot.java:140) [fabric-server-launch.jar:?]
  at net.fabricmc.loader.launch.knot.KnotServer.main(KnotServer.java:26) [fabric-server-launch.jar:?]
  at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:1.8.0_232]
  at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[?:1.8.0_232]
  at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[?:1.8.0_232]
  at java.lang.reflect.Method.invoke(Method.java:498) ~[?:1.8.0_232]
  at net.fabricmc.loader.launch.server.FabricServerLauncher.launch(FabricServerLauncher.java:61) [fabric-server-launch.jar:?]
  at net.fabricmc.loader.launch.server.FabricServerLauncher.setup(FabricServerLauncher.java:105) [fabric-server-launch.jar:?]
  at net.fabricmc.loader.launch.server.FabricServerLauncher.main(FabricServerLauncher.java:49) [fabric-server-launch.jar:?]
  Caused by: java.lang.RuntimeException: Cannot load class io.github.foundationgames.sandwichable.mixin.BuiltinModelItemRendererMixin in environment type SERVER
  at net.fabricmc.loader.transformer.FabricTransformer.transform(FabricTransformer.java:76) ~[fabric-server-launch.jar:?]
  at net.fabricmc.loader.launch.knot.KnotClassDelegate.getPreMixinClassByteArray(KnotClassDelegate.java:185) ~[fabric-server-launch.jar:?]
  at net.fabricmc.loader.launch.knot.Knot.getClassByteArray(Knot.java:208) ~[fabric-server-launch.jar:?]
  at net.fabricmc.loader.launch.knot.MixinServiceKnot.getClassBytes(MixinServiceKnot.java:47) ~[fabric-server-launch.jar:?]
  at net.fabricmc.loader.launch.knot.MixinServiceKnot.getClassNode(MixinServiceKnot.java:63) ~[fabric-server-launch.jar:?]
  at org.spongepowered.asm.mixin.transformer.MixinInfo.loadMixinClass(MixinInfo.java:1295) ~[fabric-server-launch.jar:?]
  at org.spongepowered.asm.mixin.transformer.MixinInfo.(MixinInfo.java:848) ~[fabric-server-launch.jar:?]
  ... 22 more

Fixed in 1.1.1, it was not compat.

Bit strange since I have seen Sandwichable run on servers, but I believe I know how to fix it.

I think its a incompatibility between another mod, not sure.