iPhone 14 suddenly won’t lock when I double click the right side lock button - this just started today

Double tapping the side power button will bring up Apple Pay, not lock your phone. A single tap will unlock your phone.

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Barbib1973 wrote:

Single tap, double tap… doesn’t matter, my phone is set to request a P/W or Face ID after 3-5 minutes. So far the only thing that required me to log in was restarting the phone.

again, I’ve had this phone for about 18 months, & only this afternoon did it start happening.

I'm not aware of any setting which you can set, which requires a Passcode or Face ID after 3-5 minutes. The only setting for a specific time for the screen to lock can be found in Settings > Display & Brightness > Auto Lock and there you choose an exact amount of time like 30 Seconds, 1, 2, 3, 4, or 5 Minutes. There is no 3-5 minute setting. And if you are using Face ID, assuming you're looking at the phone, when it opens, Face ID unlocks the phone and you don't have to enter your Passcode. But you do need to enter your passcode after you restart your phone. That is how it has always worked.

I'm still not clear on what you think has changed? If you want to lock your screen before Auto Lock does it, you tap the side power button once. If you want to unlock the screen and you aren't using Tap, Swipe or Raise to Wake, you tap the side power button once.