At first you should inspect the logs to see if the "Not found" disconnect is generated by our softswitch or by the server where you are routing the calls.

The outbound route should be configured as "SIP Server" and properly set on the "Routing" form.

If you own a license, please contact us with this issue at support@mizu-voip.com and we can help you with all the configuration,
(For free versions we can't provide direct support)