I might be asking the impossible but, I've been trying to create a mining dimension for our server using JED and Open terrain generator along with the Biome Bundle without much success.

I've been following the instructions on the JED mod's page and it looks like it successfully creates the dim but when I /TPJ to it my client times out, I disconnect from the server and the server throws a bunch of errors but doesn't crash. If i reconnect to the server and then try to /TPJ to the dim again, JED says it ran into an unexpected error and I have to restart the server in order to try to try to /TPJ again. Even then the same things happens.

Here is the error part of the log if it helps. https://pastebin.com/WYhzdn8y

My client times about between the lines
Loading configs for world "mining".. and
2138 world custom objects loaded.

Which Minecraft version, Forge version and version of JED is this? Do you get any errors on the client when it times out? What is the error JED gives (log please) after you log back in and try the tp a second time?

Have you tried to reproduce this in single player with more or less just JED, OTG and Biome Bundle installed? Or does this only happen on a server? Basically I need to get a reproducable, as small as possible, test setup to look into what happens. Or actually that's easy enough for me to do myself I guess, but I need all the necessary configs for the mods involved in this. So at least the JED, OTG and Biome Bundle configs you are using, where applicable.

If you use Discord and want to try to figure all this out in "more real time" without talking here in the issues, you could join my "minecraft mods" channel here: https://discord.gg/2FgywHj

Thanks maruochon, I'll join your discord.
you're right, I should have posted more information.