CPAP now reading 35, 40 when it used to be 3 or 5 AHI

Any idea why all of a sudden I am getting 30 or 40 AHI on my dreamstation CPAP machine when it was working just fine & I was getting only 3 or 5 AHI readouts. I’m using fulk face mask that hasn’t leaked. I don’t understand why it WAS working and suddenly just started showing super high AHI. I don’t get it. Help! Thanks!

The DreamStation has a feature to run a diagnostic test and/or you can ask your supplier to check your machine.
With me, I was fine for months, then increasingly worse. Had the machine checked. It was fine.
My MD sent me to a Sleep MD/Pulmonologist who changed me to APAP, with an adaptive range of 6-12 rather than a static 6 on CPAP. Most nights I’m at 9 pressure for 90% of the time, so clearly, the six was not adequate over time. He also activated several comfort features that had been set to Off. He encouraged me to not use the ramp, and I find I fall asleep much faster without it. I figured out that when the AC is running, I need a higher humidity (but not heat) setting. This also made a significant difference. The dr said to adjust that as needed. So after a six-week trial of the APAP, we agreed to keep using this, and we will review in 6 months.