16X port

When I started my rig for the first time I plugged the monitor into the video card that is plugged into the 16X port and the monitor did not work. Once I plugged (DVI) it into the motherboard the monitor works fine, Hiveos works fine for the most part. Currently, my hiveos monitor is showing 2 missing units (GPUs). Could one be because I am not using that GPU for the monitor? My motherboard is a TB250-BTC+. I am going to check for loose connections once I get home but I wanted to rule out the 16X port being a possible issue. Thoughts?

As a side note to my above post, it indicates that one is online and one is offline.