Version Info

• Minecraft, 1.21.7
• NeoForge 21.7-25 beta
• Connected Glass, 1.1.14
• Fusion, 1.2.9

Steps to Reproduce
I have a number of mods, and when I install Connected Glass, I get an error message saying that the cauldron registration is duplicated.

Crash report (~/logs/latest.log)
https://mclo.gs/kOcxQMN

Capture

I doubt this crash is related to Connected Glass 🤔
If you disable just Connected Glass and leave everything else as is, does it still crash?

If I disable Connected Glass, it starts up correctly.

You are using quite a lot of moda. Can you narrow down which other mods are required to reproduce the issue?

The problem is that it does not specify which mod is causing this problem, I have a lot of mods (111) and the game goes up, but when I put connected glass it gives me this error.

Can I give you the list of mods?

You can use binary search to find the conflicting mod(s). Disable half your mods (besides Connected Glass) and see if the game still crashes. If the crash persists, repeat with the half still enabled. If the crash goes away, repeat with the half you disabled. Eventually, you will end up with just 1 or a couple of mods.
For 111 mods, you would to repeat this just 7 times.
Dependencies do make it a bit more complicated, but the idea still applies.

Ok, I'll try, thanks anyway for the help.

Well, I did what you said, and when I install the Visual Workbench or Easy Magic mod, it crashes with the same error.

The issue should be fixed now in Fusion version 1.2.9a for Minecraft 1.21.4 - 1.21.8 SuperMartijn642/Fusion#149.
Thank you for reporting the issue!