This error occurs when the account information of the Onefax Fax printer driver is incorrect or is missing. To check whether the information is correct,

- Open your computer's Control Panel

- Go to Printers

- Right-click on Onefax Fax printer driver and click on Properties

- Click on the Ports tab, select the Onefax printer port and click on Configure port

- Enter the correct ID and the correct Password

- Click on OK