This issue also impacts client users who use new java versions. It's a super easy fix if people want to continue playing the modpack without having to hassle with java versions. Problem is that if you look up the error online, the common advice is "install java 8," however, only earlier versions of java 8 work (jdk8u302-b08 and before), the most recent does not.
This would fix #490, #468, and probalby a dozen more. The change in Forge version does not appear to cause any issues.
Sorry for the ping, especially since AaB is over a year old, but @simibubi I'd appreciate if you take a look.

I would recommended using the recommended version -> 36.2.34

Could we please update the fml installer on the release 1.3 server files please? It it so not fun trying to figure out why the pack wasn't working lmao.