I'm trying to connect my 2011 27" iMac to a 2nd monitor via an apple mini display port to dvi adapter, but the monitor isn't recognized by the iMac. I'm connecting the mini display port to the iMacs thunderbolt port. The mini display connector doesn't connect firmly into either of the thunderbolt ports, in fact, it'll fall out if I don't hold it in with my hand. The external monitor works fine when connected directly to my mac mini. Do I have a faulty adapter?