Forge version: 1.7.10-1614.58
Twilight Forest version: (twilightforest-1.7.10-2.3.7.jar)
Link to crash log: (please use a paste site such as gist, do not attach the .txt or paste the log inline)
https://pastebin.com/PZ6CdrUy

Steps to reproduce:

1. Random server crash

What I expected to happen:

What happened instead:

Unfortunately, 1.7.10 is no longer a supported version. You may need to update to 1.12.2.

^

Help info (for those who have this or a similar problem):
crutch for BiomeDecorator issues:

1. in server Bogdan-G/MinecraftForge@62c0c21
2. look commits Bogdan-G@3f71b68#diff-32e5e155d893f1f8e9111c45d70dc89aR151 or add try-catch in problem zone.

P.S. you should do it yourself as above wrote that the mod for 1.7.10 is not supported.