Fatal error on build dlc

I would like to add custom level support to my game. That works fine when I don’t use pak files. But I wan’t to use pak files for all the core stuff.

So, my idea was to use a plugin called CustomLevel, which isn’t packed. That way custom level could be copied to the plugin folder and the game could load them.

However, I can’t build the dlc, because it always fails.

The reason is a failed assertion in CookOnTheFlyServer.cpp: 6804

auto ReadDevelopmentAssetRegistry = [this, &BasedOnReleaseVersion, bVerifyPackagesExist](TArray& OutPackageList, const FString& InPlatformName)
{
FString OriginalSandboxRegistryFilename = GetBasedOnReleaseVersionAssetRegistryPath(BasedOnReleaseVersion, InPlatformName ) / TEXT(“Metadata”) / GetDevelopmentAssetRegistryFilename();

		// if this check fails probably because the asset registry can't be found or read
		bool bSucceeded = GetAllPackageFilenamesFromAssetRegistry(OriginalSandboxRegistryFilename, bVerifyPackagesExist, OutPackageList);
		if (!bSucceeded)
		{
			OriginalSandboxRegistryFilename = GetBasedOnReleaseVersionAssetRegistryPath(BasedOnReleaseVersion, InPlatformName) / GetAssetRegistryFilename();
			bSucceeded = GetAllPackageFilenamesFromAssetRegistry(OriginalSandboxRegistryFilename, bVerifyPackagesExist, OutPackageList);
		}

		if (!bSucceeded)
		{
			using namespace PlatformInfo;
			// Check all possible flavors 
			// For example release version could be cooked as Android_ASTC flavor, but DLC can be made as Android_ETC2
			FVanillaPlatformEntry VanillaPlatfromEntry = BuildPlatformHierarchy(*InPlatformName, EPlatformFilter::CookFlavor);
			for (const FPlatformInfo* PlatformFlavorInfo : VanillaPlatfromEntry.PlatformFlavors)
			{
				OriginalSandboxRegistryFilename = GetBasedOnReleaseVersionAssetRegistryPath(BasedOnReleaseVersion, PlatformFlavorInfo->PlatformInfoName.ToString()) / GetAssetRegistryFilename();
				bSucceeded = GetAllPackageFilenamesFromAssetRegistry(OriginalSandboxRegistryFilename, bVerifyPackagesExist, OutPackageList);
				if (bSucceeded)
				{
					break;
				}
			}
		}

		check(bSucceeded);
	};

I really don’t understand why it keeps failing.

I followed this tutorial: https://www.tomlooman.com/add-mod-support-to-your-unreal-engine-4-game/