When you place an outgoing call from SwitchUp, either directly from a conversation, the dial pad, or tapping on a contact, the app will display a screen that explains it will dial a SwitchUp routing number.
The app must dial the SwitchUp routing number in order to apply your SwitchLine's Caller ID to the call. Once the Caller ID of your SwitchLine is applied, the number you are trying to dial is automatically communicated to SwitchUp's routing number and your call should go through as expected.