I recall having this issue once before with adding an MR to a bound network. It was bizarre, because I was adding MR's to many of the networks, and just one of them had this issue.
In my case support got me to unbind the network, add the MR, and then rebind it. This solved my problem.
Make a note of the IP configuration (if using unique address) before doing this, as you'll need to reinstate this afterwards.