The MX does not participate in RTSP.  It mearly masses the packets on.  Your configuration will make RSTP see a 10Gb port appear to be plugged into 1 Gbe port.  I can see why it would get upset.   Only single connect the MXs to the two stacks, using only the 10Gbe cables. ... View more

I don't know the answer.   Any chance it is a Mac permission issue preventing the browser pop up window for authentication? ... View more