REMstar Auto Error E 83

My REMStar Auto has been used for 2900hours.
Recently(actually almost every night), after starting the flow for about 10-20sec, a beeping tone will be heard. The LCD showed E 83.
At first, the problem will be solved by unplug and re-plug the power cord.
However, this didn't work last night. I have tried for more than 10 times and finally give me. It is really a terrible night without CPAP.

I found out that:
E-83 means insufficient back-pressure has been detected.

But, how to manage this problem ? Thanks.

I also experienced E-83 with my RemStar Auto (original model without C-Flex). Make sure there are absolutely no air leaks in your circuit.

Mine required warranty repair by Respironics. They replaced the blower and
reconditioned the PCA board.

SWS,
Thank you very much.
There is really a tiny leakage in the hose.
The E-83 is resolved after sealing the leakage.

Unfortunately, the E 83 error recurred again.
After changing the minimal pressure from 5cmH2O to 5.6cmH2O, it worked again.
However, I am not going to take the risk anymore. I will contact Respironics for replacing of the blower and reconditioning the PCA board.