I loaded a Forge 1.12.2 Server and it halted while loading. No crash report was returned.
debug.log
modlist.txt

The server has worked well prior to the installation of Mixin and ImmersivePortals.
Using forge-1.12.2-14.23.5.2847-universal.jar on Client and Server

Lmk if you need any more info

Edit: Fixed modlist

Found out Mixin was the problematic mod. Sorry