Cannot Send or Receive Even Though a Connection has been Correctly Established

Make sure that the PC-FAX driver is installed on the computer. The PC-FAX driver is installed with FAX Utility. Follow the steps below to check if it is installed.

Select System Preferences (or System Settings) from the Apple menu > Printers & Scanners (or Print & Scan or Print & Fax), and then make sure the printer (fax) is displayed. The printer (fax) is displayed as "FAX XXXX (USB)" or "FAX XXXX (IP)". If the printer (fax) is not displayed, click [+] and then register the printer (fax).

Select System Preferences (or System Settings) from the Apple menu > Printers & Scanners (or Print & Scan or Print & Fax), and then double-click the printer (fax). If the printer is paused, click Resume (or Resume Printer).

Try the resolutions for fax connection and fax settings.