Thanks for your question and sorry for the delay in responding. mDNS, a.k.a. Bonjour, can be tricky at times, but there's not much of a system to it. If both Audio-Midi setup (network midi) is searching and MD is still searching, it usually indicates either that 1) they're not connected on a lower, networking level or 2) there's a conflict with the DNS names.
Basically, there's no one solution that's definitely going to work, but if you try a bunch of things, eventually you'll get connected. I'd start with restarting the computer. Note that you do NOT need to start Ableton to get the connection happening. If that doesn't work, create a NEW network session. Make sure the session, on the bottom left, shows "allow anyone to connect to me."
Let me know how this goes and we'll troubleshoot it going forward.
Thanks for buying MDP and thanks for your patience as we get this figured out.