I experience the same thing. What has helped (sometimes) for me is to go to the Parallels network settings, and change the network source to "Default Adapter" then restart windows.

Then after the restart I go bak to network settings and change back to "Shared Network" and restart windows again. It's a little time consuming, but seems to work 70% of the time.

It's also worth double checking to make sure your VS is trying to access the correct IP address on your mac.