HP motherboards often use a proprietary pinout. Standard aftermarket cases use a generic HD Audio connector. If Pin 4 or Pin 10 (depending on the model) isn't grounded, the BIOS triggers the 917 error.
The error is triggered by a continuity check performed by the motherboard. If the circuit isn't completed, the BIOS assumes the hardware is missing or broken. 917-front audio not connected
A physical break in the front audio jack or the cable itself. HP motherboards often use a proprietary pinout
The cable connecting the front ports to the motherboard has wiggled free. 917-front audio not connected