I’ve run into this with increasing frequency in my Server 2012R2 clusters, and it ended up being WMI corruption. IPConfig would show correct IP addressing (and even the teamed NICs created with Windows teaming), and ping would work; however, the network connections dialog box (ncpa.cpl) was completely empty, Server Manager said teaming was disabled, launching the teaming administration page (lbfoadmin.exe) would show “Host Unmanageable” as the status, and attempting to make any connection to any other machine other than ping would result in failure (for example, \\server\share would fail immediately with the host being unavailable).
Here are the steps I needed to use to get the machines up and running again (and I’ve restored from failed backups on a few to test and retest these steps, and in this particular order which did seem to matter, to validate):