We've got this mod installed on Minecraft 1.18.1 local server but when we try to open the portal nothing happens.

The server is showing this error message

"Cannot invoke "net.minecraft.world.level.Level.m_8055_(net.minecraft.core.BlockPos)" because "worldIn" is null"

We've tried restarting the clients, server etc but still no joy.

I'm sorry to reply to this so late. But did version 1.13.4 of this mod fix the issue for you? I did fix something that could cause this.

For me there is no error text, it just wont activate the portal no matter what I di

Thank you for the report. This is a previously unheard of issue.

I've tested myself in a dedicated server environment with a few other mods installed and it does work for me. Can I see a whole logfile please? I'm mainly interested in which other mods are installed. Because that error alone seems to indicate that dimdungeons:dhungeon_dimension wasn't registered or otherwise somehow doesn't exist.

If this is still happening in 1.18.2 you can make a new ticket or let me know however you want. I assume it's working now?