UHT Unparsed class problem

I’m getting this error from UHT while trying to compile my project:

Unparsed class ‘MyServerBeaconClient’ found while validating DependsOn entries for 'MyServerBrowser’

The project code is split between 3 modules: Common, Client, and Server. The MyServerBeaconClient class is defined in the common module and the MyServerBrowser class is defined in the Client module. I’m guessing the problem is due to the client module trying to use a class defined in another module. How do I make UHT happy?