PC faxes quit during sending.
It is possible that your PC is overloaded with activity like sending more than one fax at a time, or starting applications that take a long time.
Try to reduce the activity on your PC while faxes are being sent or received.
Faxes routed to the PC are printed instead.
If the HP OfficeJet LX Manager is not running, faxes are printed on receipt. If your PC is too busy, faxes are printed on receipt.
The HP OfficeJet LX Manager may have lost the connection to the device. Open the front cover and make sure that the HP OfficeJet LX Manager says "Close Cover." If not, check the cable connection to the device. If the cable seems OK, close, then restart the HP OfficeJet LX Manager.