Trouble with new AirPods Pro 3

Hi.

I bought Apple AirPods Pro 3 today and I'm having trouble with the button on the earbuds.

The buttons only work for volume up and down. No other gestures, such as pausing the audio or skipping tracks, work.

What could be causing this? I've tried re-pairing the earbuds with my iPhone 15, but to no avail.