Hanway Lin,
Here are some of the solutions:
- Is the user spawning in the item via BP cheat command, this seems to not work correctly with structures making it not placeable.
- Is there another MOD running above your MOD that has not been updated and uses the placement array (assuming that MOD is running the latest devkit build and or requires a GUID update, which forces all users to completely redownload the MOD)
- Did you add the structure to the “placeable structures array” ? i assume so if others can place the item. In that case i recommend you inform user to remove MODids from their .ini until they figure out what MOD is causing the conflict.