Lexmark MS812de
Go to the printer’s embedded web page (EWS). Enter MFPs IP address in browser URL. For example ‘https://192.168.5.1'.
From the embedded web page, navigate to: Settings > Fax Settings > Analog Fax Setup > Fax Transport and Check if it is set to ‘Analog’ or ‘etherFAX’.
LEGACY ID: SO9066
Unable to 'Receive' a Fax with Laser Multifunction Printers (MFPs)
Fax error codes and recommendations for the X64x, X65x X73x, X77x, X78x, X79x, X85x, X86x, X945, and X92x Series MFPs