Tried with both normal modlists and with only AS and Forge. Both crash while loading with a -1 error.

https://pastebin.com/Es298Cew This is a pastebin of the crashlog it left behind.

No idea what causes it since it was working fine a few days ago.

Forge has changed its registration system if you didn't notice that being discussed lately.

Issues like this are the result of these changes - and i suspect more mods than just mine experience issues. Use a bit of an older forge version to run it or wait 1-2 days for me to finish what i'm working on and then redo registration.

Updated AS to the new registry system of forge. 1.5.4 is runnable with the newer forge versions for 1.12