Common reasons for "Scan Failure"

Windows Servers

• The firewall on the target server may be blocking connections from the appliance
• The firewall on the target server may be blocking some of the ports required by the appliance
• The Remote Registry service on the target might not be running
• The Remote Procedure Call (RPC) service on the target might not be running
• The target server may have all file-sharing (even of the administrative shares) turned off.

In order to test the credentials used by the appliance are valid, you should attempt to log in to the target using Remote Desktop Connection.
If that succeeds, then you need to use the wbemtest tool to connect to the target, using the same credentials.

If the WBEM connection succeeds you should get a screen like this:

If you get an error message which says "The RPC server is unavailable" you need to start (or restart) the RPC Service on the target.

To test Remote Registry you can use "Regedit" from any Windows server or desktop to connect to the target server registry

If this succeeds, then the remote registry is enabled. If not you may need to start (or restart) the Remote Registry service.

Unix/Linux servers

Unable to connect to SSH

If you know your credentials are valid, but the appliance can still not connect, try logging in to the appliance and using SSH to connect directly.

An error of the form "Unable to negotiate with 203.0.113.0: no matching key exchange method found." implies that the target and your appliance  do not have a shared key exchange method. (This happens with very out of date targets.)

If you get an error like "Connection closed by 203.0.113.0 port 22" it implies the SSH server on the target has crashed or is not running.