linux - Why does net rpc shutdown fail with the right credentials?

The command

$ net rpc SHUTDOWN -f -I xxx.xxx.xxx.xxx -U uname%psswd

Fails with the following errors:

Could not connect to server xxx.xxx.xxx.xxx
The username or password was not correct.
Connection failed: NT_STATUS_LOGON_FAILURE
Could not connect to server xxx.xxx.xxx.xxx
The username or password was not correct.
Connection failed: NT_STATUS_LOGON_FAILURE

When the credentials are definitely, absolutely correct. Whats going on?

Answer

Disable simple file sharing on the remote host by going to

My Computer > Tools > Folder Options > View  

And UNCHECK simple file sharing

Also punch the appropriate holes in your firewall by going

Control Panel > Security Center > Windows Firewall > Exceptions 

and CHECK "File and Printer Sharing"

Also on the Advanced tab > ICMP Settings CHECK "Allow incoming echo request"

More info here.