Solution #00004357
Scope:
This solution applies to Yosemite Server Backup 8.7 and newer
Answer:
One likely cause relates to the virtual machine lacking a configured network adapter. This appears to be an issue related to the way Hyper-V manages snapshots of its Guest machines. If you add the appropriate network adapter, it should resolve the issue.
Here is a forum posts from Microsoft that relates to this same issue:
Link to this page:
https://campus.barracuda.com/solution/50160000000Hr4pAAC