When sending a fax in monochrome, the scanned document is temporarily stored in the printer's memory. Therefore, sending a lot of pages may cause the printer to run out of memory and stop sending the fax. You can avoid this by enabling the Direct Send feature, however, it takes longer to send the fax because the printer performs scanning and sending simultaneously. You can use this feature when there is only one recipient.
You can find the menu on the printer's control panel below.
Fax > Fax Settings > Direct Send.