Apple tv gen 3 "not authorized"; Apple tv gen 2 works though

I have two ATVs...both connecting to my iTunes library via wireless through my router.

I have my iTunes library on my Mac which is also on my home network.

One is an ATV gen 2 and I can stream movies and music from my iTunes library with no problem.

One is a ATV gen 3 and I can only stream music from my iTunes library.

If I try to stream movies I get the "not authorized" message.

On the same ATV gen 3 I can stream movies directly from the iTunes store if i want to watch something I have already purchased or recently rented

It seems obvious that this issue has nothing to do with Authorization on my Mac since I can stream from my iTunes library to my gen 2 ATV and music to my gen 3 ATV.

I have restarted the gen 3 ATV and downloaded content (rented a movie) from the iTunes store...I had read other posts that said those steps may fix the issue but they didn't.

Any suggestions? I've run out of ideas and found no other solutions from the other posts I've read.

Thanks!