Hi I am having an issue on my Fabric 1.20.1 server where everytime I try to tp to the creative world it crashes and says that it is missing the dimension Building_Dimension:Overworld and I have to be teleported back using a repeating command block. I have Fabric API and Fantasy Library installed as well as the Multiworld Mod.

I have attached the latest log, hope you can figure this out. I really want a creative world to keep people on my server! Please let me know if you need more info or context.

latest (4).log

additionally, I tried doing it in a singleplayer and it crashed me to desktop so it isn't a server issue.

Hello, thanks for opening an issue. I've looked a bit into the file and cant find the issue immediately.
I'll look more into it this week, I've never seen packet, is that the server log or single player log ? If it's single player, if you have the server only logs that could also help.

Are you using a premade modpack ? If so, I could download it to test more in depth.

Little follow up, Could you try removing ImmersivePortals.
If it works again, I'll try to integrate it to work.

Thanks for the response! I removed Immersive portals, and it worked! So, if it is possible to integrate that mod, that would be awesome! I am also having a new issue where every time I tp to the creative world and back (in single player) my advancements get reset. If you want to test the modpack it is a custom modpack but it was approved by CurseForge, so just search "SteamCraft - Train focus". You will have to add the Building Dimension mod since it is server-side only. Thank you again for responding so quickly!

Here are the singleplayer logs:
latest.log

No problem, for the achievements It should give them back when going back I'll try to test it a bit more as giving Achievements is a bit hard and something might be broken.

Okay, after a bit more testing I do retain my advancements it just gives the popups every time. A tad annoying, but not the end of the world. I would rather have immersive portals be compatible :)

Yes i tried to patched it by turning the gamerule off but it seems like it's not working, might be due to the server-side only. I'll test it more.
For immersive portals I've looked a bit online and haven't found a quick fix but I hope it's not due to the server-side only or the fact I'm loading dimension just after the server started.

I wont be avaliable for a few hours, if you need to reach me you may contact me on discord "lordmaximus05". I seem to be having a lot of unique problems such as: I logged off in the creative world and lost my inventory lol (have replicated so not a one time issue) so I will do some more intensive testing tonight by removing mods and such so you don't have to do so much work!

Sure, I'll send you a request.
Also if you want to only include the mod for your server, you could do a server zip for example like : https://www.curseforge.com/minecraft/modpacks/create-astral/files/4729689
At the bottom of the page there is "Additional files" with the server zip, also useful if there are others server side mods.

A fix is comming in the next update and is currently working.