I'm having the same exact problem. I've been working with Solarwinds tech support to try and resolve the issue. Please help!
The issue of the Monitor stuck in loading phase is a bug that occurs in a specific scenario that relates to the exchange server environment.
Thanks to some of the folks on this post who helped to diagnose and test this issue, we have isolated the bug and tested the fix for it. We are putting together a build that we will post shortly. You should be able to download the updated build and install on top of your current environment.