Can't perform a factory reset on AirPods Max

Question

According to Apple's instruction factory reset is performed by pressing and holding both NC button and Digital Crown until the indicator light flashes amber and then white. However, in my case the light only flashes amber and nothing happens next. I tried holding buttons a little bit longer but the white flash never happened.

Headphones are around 90% charged, so it's not a battery issue. Tried in/out of case and with/without power cable, nothing worked.

Any ideas?

Answer 1

Just brought them to the local authorized service to get a replacement.