DaemonUmbra

How did you install the modpack?

Please read the Logs section of my signature below and provide the appropriate log in the appropriate manner.

1.8.9 is no longer supported on this forum due to its age. Please update to a modern version of Minecraft to receive support.

This entire issue is apparently surrounding your workspace apparently utilizing some mcp folder which shouldn't exist. Can you show me where your IDE mentions this mcp folder?

Please restart your launcher, reproduce this error, close your launcher, and share launcher_log.txt via one of the paste sites in my signature

I'm not 100% of what you're saying because you don't appear to be using English as I understand it. It sounds like you're using Hamachi and trying to set your server to use a specific port that Hamachi opens?

Please don't hijack other peoples threads. If you have an issue please make your own thread.

Upload debug.log to one of the paste sites listed in my signature

That "No syncable config" is not related to you disconnecting. Please provide debug.log from both client and server using one of the paste sites listed in my signature.

Try running the server from the command line, what does it say?

Try the latest version of Forge for 1.12.2

Forge for 1.13+ requires Java 8-10 Forge for 1.12.2- requires Java 8

User was banned for piracy. Buy the game.

Oh I was looking at 1.14.4, apparently net.minecraftforge.gradle.forge was correct in 1.12.2 In this case please provide your build.gradle using one of the paste sites in my signature

1.6.4 is no longer supported on this forum due to its age. Please update to a modern version of Minecraft to receive support.

1.7.10 is no longer supported on this forum due to its age. Please update to a modern version of Minecraft to receive support.

Your build.gradle is in fact wrong, it's net.minecraftforge.gradle, not net.minecraftforge.gradle.forge

At this time I have to say McJty's tutorial is the least bad. If you have an MCP folder you're doing something wrong because MCP is not longer really a thing

User was banned for piracy. Buy the game.

This crash report says you're in 1.13.2 What launcher are you using? Please provide a screenshot

Please keep this forum in English. Why are you using 1.13.2?

This sounds like you're doing things incorrectly and asking us to help when it breaks

Why the heck do you even have an MCP folder?

Learn Java before you attempt modding. Oh, I missed the sarcasm part. However you do seem to be struggling with a few things that I would consider basic.