My auto lock isn’t working

What does "isn't working" mean exactly?

Does it mean you are not allowed to change your 30 second setting? If so, that is correct, because you have chosen to use low-power mode which restricts the auto-lock setting to 30 seconds.

In addition to what sberman is referring to, when you look at your battery icon, you can see that it is a yellow color, which tells you that you are in Low Power mode. Just another little hint to remind you that you are in low power. And the text in the phone just below Raise to Wake explains why you cannot change it and why it is set at 30 seconds.