We had this issue on multiple seeminly unrelated Windows systems. It ended up being the antivirus product we were using. The AV client was updated and grabbed on to the DCOM server. It wasn't allowing any connections on port 135 until the system was rebooted. Here is the error from the command line.
[librpc/rpc/dcerpc_connect.c:337:dcerpc_pipe_connect_ncacn_ip_tcp_recv()] failed NT status (c0000236) indcerpc_pipe_connect_ncacn_ip_tcp_recv
[librpc/rpc/dcerpc_connect.c:828:dcerpc_pipe_connect_b_recv()] failed NT status (c0000236) in dcerpc_pipe_connect_b_recv
[wmi/wmic.c:196:main()] ERROR: Login to remote object.
NTSTATUS: NT_STATUS_CONNECTION_REFUSED - NT_STATUS_CONNECTION_REFUSED
Once the system was restarted it was all back to normal.