Update Failure with Minecraft - Minecraft Java FTB Unstable Not Launching

[ThePotatoKing]

You need to switch the server type back to Forge and set the right Forge version.
Full guide here:

Forge Frequently Asked Questions

Forge Frequently Asked Questions How do I run Forge using: start.sh/start.bat? No need! AMP handles all that for you. Just select the version of Forge you’ll need, hit update, and start your server. Where do I put custom start up arguments? You can find this options under: Configuration → Java and Memory → Additional java options I installed a modpack using AMP’s FTB downloader, why did it start in Vanilla? or The update manager reported a successful update, but ./Minecraft/minecraft_server.j…