According to the info collected here it's a "already running this task" issue - I hope you know a way to resolve this?
leafreynolds/soulhome#5

I confirmed both mods crash together, the rest of the pack seems unaffected, after disabling CBC in a test profile and entering the SH dimension.
Here's a copy of the crash log so you can look up what's going wrong. The SH dev also looked at the situation and gave hints in the linked github issue.
crash-2023-11-15_20.26.49-server.txt

Technical detail is something along the lines of:

• Soulhome or its dependencies unfreezes the dimension registry so it can later add dimensions as needed
• Chunk By Chunk unfreezes, inserts its dimensions and re-freezes the dimension registry on start up
• When you first use the soulhome key it tries to insert a new dimension into the dimension registry and because Chunk By Chunk has refrozen the registry.

So fix is I just won't re-freeze the dimension registry (which I was doing to minimise impact on standard minecraft behavior).

Fixed in 2.1.1

Thanks a lot for your fix! I'll eagerly await the update 2.1.1 :)

Thanks again! I've successfully tested the update, it works now!

New information, the crash doesn't affect not petrified worlds (where I used the CBC config to spawn in the overworld, instead)
I could freely enter and leave the Soulhome dimension there.