It seems "MTPB23108(InfiniHost)" isn't supported on Win2012 R2. Below is a link to mellanox windows driver download page.
You need to select WinOF Download --> driver version than --> OS version. In respect to your OS, Driver version 4.55 & up supports Windows Server 2012 R2, however, from the release notes, Does not support MTPB23108 (InfiniHost).
MTPB23108 (InfiniHost) is an older product. Perhaps, you need to consider purchasing ConnectX3 or Connectx3-Pro or Connectx4.