Dolby Digital settings

I am using the raspberry pi 3 , Kodi , OSMC. I have it connected to my home theater receiver using 5.1 speakers and all I can get on movie audio is PLII Cinema? My receiver is capable of decoding Dolby Digital. I have passthru enabled as well as AC3 and other Dolby Digital selections. How do I enable or get Dolby Digital to work on Movies? What are the settings?