Forge won't accept spongeforge as mod

whenever I try to set up a spongeforge server, I keep getting the same error suggesting that spongeforge isn’t a mod. The server still starts up, but I can’t do anything with sponge

[19:41:04] [main/INFO] [LaunchWrapper]: Loading tweak class name net.minecraftforge.fml.common.launcher.FMLServerTweaker
[19:41:04] [main/INFO] [LaunchWrapper]: Using primary tweak class name net.minecraftforge.fml.common.launcher.FMLServerTweaker
[19:41:04] [main/INFO] [LaunchWrapper]: Calling tweak class net.minecraftforge.fml.common.launcher.FMLServerTweaker
[19:41:04] [main/INFO] [FML]: Forge Mod Loader version 14.23.5.2838 for Minecraft 1.12.2 loading
[19:41:04] [main/INFO] [FML]: Java is Java HotSpot™ 64-Bit Server VM, version 1.8.0_321, running on Windows 10:amd64:10.0, installed at C:\Program Files\Java\jre1.8.0_321
[19:41:04] [main/INFO] [FML]: Searching C:\Users\dalfi\Desktop\sponge server.\mods for mods
[19:41:04] [main/INFO] [LaunchWrapper]: Loading tweak class name net.minecraftforge.fml.common.launcher.FMLInjectionAndSortingTweaker
[19:41:04] [main/INFO] [LaunchWrapper]: Loading tweak class name net.minecraftforge.fml.common.launcher.FMLDeobfTweaker
[19:41:04] [main/INFO] [LaunchWrapper]: Calling tweak class net.minecraftforge.fml.common.launcher.FMLInjectionAndSortingTweaker
[19:41:04] [main/INFO] [LaunchWrapper]: Calling tweak class net.minecraftforge.fml.common.launcher.FMLInjectionAndSortingTweaker
[19:41:04] [main/INFO] [LaunchWrapper]: Calling tweak class net.minecraftforge.fml.relauncher.CoreModManager$FMLPluginWrapper
[19:41:05] [main/INFO] [FML]: Found valid fingerprint for Minecraft Forge. Certificate fingerprint e3c3d50c7c986df74c645c0ac54639741c90a557
[19:41:05] [main/INFO] [LaunchWrapper]: Calling tweak class net.minecraftforge.fml.relauncher.CoreModManager$FMLPluginWrapper
[19:41:05] [main/INFO] [LaunchWrapper]: Calling tweak class net.minecraftforge.fml.common.launcher.FMLDeobfTweaker
[19:41:06] [main/INFO] [LaunchWrapper]: Loading tweak class name net.minecraftforge.fml.common.launcher.TerminalTweaker
[19:41:06] [main/INFO] [LaunchWrapper]: Calling tweak class net.minecraftforge.fml.common.launcher.TerminalTweaker
[19:41:06] [main/INFO] [LaunchWrapper]: Launching wrapped minecraft {net.minecraft.server.MinecraftServer}
[19:41:08] [Server thread/INFO] [minecraft/DedicatedServer]: Starting minecraft server version 1.12.2
[19:41:08] [Server thread/INFO] [FML]: MinecraftForge v14.23.5.2838 Initialized
[19:41:08] [Server thread/INFO] [FML]: Starts to replace vanilla recipe ingredients with ore ingredients.
[19:41:08] [Server thread/INFO] [FML]: Invalid recipe found with multiple oredict ingredients in the same ingredient…
[19:41:08] [Server thread/INFO] [FML]: Replaced 1227 ore ingredients
[19:41:09] [Server thread/INFO] [FML]: Searching C:\Users\dalfi\Desktop\sponge server.\mods for mods
[19:41:09] [Server thread/INFO] [FML]: Forge Mod Loader has identified 4 mods to load
[19:41:09] [Server thread/WARN] [FML]: Missing English translation for FML: assets/fml/lang/en_us.lang
[19:41:09] [Server thread/INFO] [FML]: FML has found a non-mod file spongeforge-1.12.2-2838-7.4.7-sources.jar in your mods directory. It will now be injected into your classpath. This could severe stability issues, it should be removed if possible.
[19:41:09] [Server thread/INFO] [FML]: Attempting connection with missing mods [minecraft, mcp, FML, forge] at CLIENT
[19:41:09] [Server thread/INFO] [FML]: Attempting connection with missing mods [minecraft, mcp, FML, forge] at SERVER
[19:41:09] [Server thread/INFO] [FML]: Processing ObjectHolder annotations
[19:41:09] [Server thread/INFO] [FML]: Found 1169 ObjectHolder annotations
[19:41:09] [Server thread/INFO] [FML]: Identifying ItemStackHolder annotations
[19:41:09] [Server thread/INFO] [FML]: Found 0 ItemStackHolder annotations
[19:41:10] [Server thread/INFO] [FML]: Configured a dormant chunk cache size of 0
[19:41:10] [Forge Version Check/INFO] [forge.VersionCheck]: [forge] Starting version check at http://files.minecraftforge.net/maven/net/minecraftforge/forge/promotions_slim.json
[19:41:10] [Server thread/INFO] [FML]: Applying holder lookups
[19:41:10] [Server thread/INFO] [FML]: Holder lookups applied
[19:41:10] [Server thread/INFO] [FML]: Applying holder lookups
[19:41:10] [Server thread/INFO] [FML]: Holder lookups applied
[19:41:10] [Server thread/INFO] [FML]: Applying holder lookups
[19:41:10] [Server thread/INFO] [FML]: Holder lookups applied
[19:41:10] [Server thread/INFO] [FML]: Applying holder lookups
[19:41:10] [Server thread/INFO] [FML]: Holder lookups applied
[19:41:10] [Server thread/INFO] [FML]: Injecting itemstacks
[19:41:10] [Server thread/INFO] [FML]: Itemstack injection complete
[19:41:10] [Server thread/INFO] [minecraft/DedicatedServer]: Loading properties
[19:41:10] [Server thread/INFO] [minecraft/DedicatedServer]: Default game type: SURVIVAL
[19:41:10] [Server thread/INFO] [minecraft/DedicatedServer]: Generating keypair
[19:41:10] [Server thread/INFO] [minecraft/DedicatedServer]: Starting Minecraft server on *:25565
[19:41:10] [Server thread/INFO] [minecraft/NetworkSystem]: Using default channel type
[19:41:10] [Server thread/INFO] [FML]: Applying holder lookups
[19:41:10] [Server thread/INFO] [FML]: Holder lookups applied
[19:41:10] [Server thread/INFO] [FML]: Injecting itemstacks
[19:41:10] [Server thread/INFO] [FML]: Itemstack injection complete
[19:41:10] [Server thread/INFO] [FML]: Forge Mod Loader has successfully loaded 4 mods
[19:41:10] [Server thread/INFO] [minecraft/DedicatedServer]: Preparing level “world”
[19:41:10] [Server thread/INFO] [FML]: Injecting existing registry data into this server instance
[19:41:11] [Server thread/INFO] [FML]: Applying holder lookups
[19:41:11] [Server thread/INFO] [FML]: Holder lookups applied
[19:41:11] [Server thread/INFO] [FML]: Loading dimension 0 (world) (net.minecraft.server.dedicated.DedicatedServer@24f0ff5d)
[19:41:11] [Forge Version Check/INFO] [forge.VersionCheck]: [forge] Found status: OUTDATED Target: 14.23.5.2859
[19:41:11] [Server thread/INFO] [minecraft/AdvancementList]: Loaded 488 advancements
[19:41:11] [Server thread/INFO] [FML]: Loading dimension -1 (world) (net.minecraft.server.dedicated.DedicatedServer@24f0ff5d)
[19:41:11] [Server thread/INFO] [FML]: Loading dimension 1 (world) (net.minecraft.server.dedicated.DedicatedServer@24f0ff5d)
[19:41:11] [Server thread/INFO] [minecraft/MinecraftServer]: Preparing start region for level 0
[19:41:12] [Server thread/INFO] [minecraft/MinecraftServer]: Preparing spawn area: 56%
[19:41:13] [Server thread/INFO] [minecraft/DedicatedServer]: Done (2.307s)! For help, type “help” or “?”
[19:41:13] [Server thread/INFO] [FML]: Unloading dimension -1
[19:41:13] [Server thread/INFO] [FML]: Unloading dimension 1

Your sponge forge “mod” spongeforge-1.12.2-2838-7.4.7-sources.jaris a “sources.jar” file which is a developer file, not sponge forge itself.

So the error is right in the fact its not a mod. Please download sponge forge from the official download site SpongeDownloads and click the “download” button, not the “sources” button.

Hope that helps