DaemonUmbra

Don't make custom clients. Don't use MCP. 1.12.2 is no longer supported, update to a modern version for support.

1.12 is no longer supported on this forum. Please update to a modern version of Minecraft to receive support.

Please keep this forum in English. Are you saying you can’t download Forge’s installer? Why?

1.10 is no longer supported on this forum. Please update to a modern version of Minecraft to receive support.

1.12 is no longer supported on this forum. Please update to a modern version of Minecraft to receive support.

1.12 is no longer supported on this forum. Please update to a modern version of Minecraft to receive support.

Please provide debug.log as described in the EAQ and the logs section of my signature below

1.7 is no longer supported on this forum. Please update to a modern version of Minecraft to receive support.

https://adoptopenjdk.net

1.7 is no longer supported on this forum. Please update to a modern version of Minecraft to receive support.

Please keep this forum in English. Those updates actually have no changes from a Player's perspective, they have been updated to the same toolset used by the more modern branches so mod devs who ignore our advice about updating will stop complaining when the old toolset breaks.

1.12 is no longer supported on this forum. Please update to a modern version of Minecraft to receive support.

1.12.2 - No MCP - No Update to a supported version (currently 1.14.4 and 1.15.2) and use Forge

Use Java 8

1.12 is no longer supported on this forum. Please update to a modern version of Minecraft to receive support.

Yes

1.12 is no longer supported on this forum. Please update to a modern version of Minecraft to receive support.

1.12 is no longer supported on this forum. Please update to a modern version of Minecraft to receive support.

1.12 is no longer supported on this forum. Please update to a modern version of Minecraft to receive support.

1.7 is no longer supported on this forum. Please update to a modern version of Minecraft to receive support.

You were also already told that 1.12.2 isn't supported anymore.

He was playing an old, unsupported version and didn't read the bit of the log that told him exactly what was wrong. Locking...

If you can reliably reproduce the issue then do so and provide a log from that run, you don't need to provide a log of the server running for a while before the issue occurs

The Logs section of my signature below has a video on how to run a Twitch pack without Twitch, try that

I wish Twitch wasn't so unreliable. The logs section of my signature has a video on how to run a Twitch pack without using Twitch, try that