I have three Deco BE 11000 units and added an outdoor DECO 50 unit. No problems. 

I decided to add a 4th BE 11000 unit and started having problems with units reporting offline. Most commonly it is the newest unit. That unit is farthest from the main node, BUT all are connected via Cat 5 cables via the control box downstairs. That is each SHOULD be communicating via hardwired Cat 5. I have reset and restarted the new unit many times but have the same problem. Occasionally the DECO 50 unit goes offline but that has been pretty stable for a while. 

Any solutions?