Cannot place light at ceiling plan

[p.n.m.chan]

I have tried to place the ceiling light at the ceiling of the ceiling plan, but it doesn't allow me to do so. The mouse sign changes to a stop sign. How to solve this problem? Thank You!

[barthbradley]

Is your fixture a ceiling-hosted family? Can you place the fixture on the ceiling in 3D View?  

[p.n.m.chan]

The item is a ceiling item default at the library of Revit 2021. I cannot place it in the 3D view.

[barthbradley]

You first need to place a Ceiling (Architecture tab) in the Ceiling Plan View. 

[p.n.m.chan]

Yep. Automatic ceiling is already placed.

[barthbradley]

Are you sure? Doesn't sound like it if your CEILING-HOSTED family doesn't detect it in 3D View.