What on earth is happening, here? Is it an incompatability with a mod I have? I can't understand this error at all. Please help!

java.util.concurrent.ExecutionException: java.lang.NullPointerException: Cannot invoke "umpaz.brewinandchewin.common.BnCConfiguration$Common.keg()" because the return value of "house.greenhouse.greenhouseconfig.api.GreenhouseConfigHolder.get()" is null

If it reads as an incompatability, happy to provide modlist, but I don't think it is?

[21:43:08] [main/WARN]: Failed to load datapacks, can't proceed with server load. You can either fix your datapacks or reset to vanilla with --safeMode
java.util.concurrent.ExecutionException: java.lang.NullPointerException: Cannot invoke "umpaz.brewinandchewin.common.BnCConfiguration$Common.keg()" because the return value of "house.greenhouse.greenhouseconfig.api.GreenhouseConfigHolder.get()" is null
at java.base/java.util.concurrent.CompletableFuture.reportGet(CompletableFuture.java:396) ~[?:?]
at java.base/java.util.concurrent.CompletableFuture.get(CompletableFuture.java:2073) ~[?:?]
at knot/net.minecraft.server.Main.main(Main.java:229) [server-intermediary.jar:?]
at net.fabricmc.loader.impl.game.minecraft.MinecraftGameProvider.launch(MinecraftGameProvider.java:506) [fabric-loader-0.17.3.jar:?]
at net.fabricmc.loader.impl.launch.knot.Knot.launch(Knot.java:72) [fabric-loader-0.17.3.jar:?]
at net.fabricmc.loader.impl.launch.knot.KnotServer.main(KnotServer.java:23) [fabric-loader-0.17.3.jar:?]
at net.fabricmc.loader.impl.launch.server.FabricServerLauncher.main(FabricServerLauncher.java:69) [fabric-loader-0.17.3.jar:?]
Caused by: java.lang.NullPointerException: Cannot invoke "umpaz.brewinandchewin.common.BnCConfiguration$Common.keg()" because the return value of "house.greenhouse.greenhouseconfig.api.GreenhouseConfigHolder.get()" is null
at knot/umpaz.brewinandchewin.common.crafting.KegFermentingRecipe.method_8110(KegFermentingRecipe.java:133) ~[BrewinAndChewin-fabric-4.4.0+1.21.1.jar:?]
at knot/net.player005.recipe_modification.api.RecipeModification.applyModifications(RecipeModification.java:306) ~[recipe_modification-fabric-1.21.1-0.1.1.jar:?]
at knot/net.player005.recipe_modification.api.RecipeModification.onRecipeManagerLoad(RecipeModification.java:284) ~[recipe_modification-fabric-1.21.1-0.1.1.jar:?]
at knot/net.minecraft.class_5350.handler$dbk000$recipe_modification$initialiseRecipeModification(class_5350.java:3033) ~[server-intermediary.jar:?]
at knot/net.minecraft.class_5350.method_40421(class_5350.java:94) ~[server-intermediary.jar:?]
at knot/net.minecraft.class_7237.method_42097(class_7237.java:52) ~[server-intermediary.jar:?]
at java.base/java.util.concurrent.CompletableFuture$UniApply.tryFire(CompletableFuture.java:646) ~[?:?]
at java.base/java.util.concurrent.CompletableFuture$Completion.run(CompletableFuture.java:482) ~[?:?]
at knot/net.minecraft.class_156.method_43498(class_156.java:1024) ~[server-intermediary.jar:?]
at knot/net.minecraft.class_156.method_43499(class_156.java:1012) ~[server-intermediary.jar:?]
at knot/net.minecraft.server.Main.main(Main.java:182) ~[server-intermediary.jar:?]
... 4 more

Full log from start of issue above.

using Creeperhost as a server host, if that is at all relevant.