Display problem after connection established

I have a unique problem that I'm not sure how to solve.  I have a Desktop PC, a headless Intel NUC miniPC and an Android phone.  I log in to the NUC via either the desktop or phone.  

When on the same local network, connected to the internet, I can login to the NUC from either device and it displays properly.

However, sometimes without internet, but still on the same local network, I need to login to the NUC via direct IP address on the local network.  So I try to establish a connection to the NUC on my Android phone, and Teamviewer asks for the password which I put in correctly.  At this point the phone app displays "Please wait while connecting" and sits there forever.  It never displays the NUC desktop.  However, if I have a monitor attached to the NUC I can see that TV thinks there is a connection made.  Also, I can connect the desktop PC to the NUC via direct IP and it also displays properly. 

So to summarize, the Android app will not display the remote computer (NUC) via direct IP address, even though the NUC teamviewer session thinks it's connected.

Any idea how to get the phone to display the NUC properly?