We are playing on a server with forge 43.3.0 and are not able to place blocks inside the tents, while in singleplayer it's possible. Even the players with Operator rights are not able to place stuff inside the tents.

The modification is part of a wild west themed modpack with 65 other mods.

Minecraft version: 1.19.2
Forge version: 43.3.0

I found the problem: The interiors were all generated outside the world border.