Press and hold the Sleep/Wake button until the slider appears, then drag the slider. Press either the Sleep/Wake or Home button, then drag the slider. If not, there is no need to be disappointed as there are many. Once your iPhone has rebooted, check out if the WiFi disconnects when iPhone is asleep problem is gone. Press and hold the Sleep/Wake button until the Apple logo appears. To force restart iPhone 6s, iPhone 6s Plus, iPhone SE or earlier devices, press and hold both the Home and sleep/wake buttons simultaneously. To adjust the timing, go to Settings > General > Auto-Lock. IPhone locks automatically if you don’t touch the screen for a minute or so. On earlier iPhone models, the Sleep/Wake button is on the top edge: On iPhone 6, iPhone 6 Plus, and later, the Sleep/Wake button is on the right side: You can also listen to music and adjust the volume. You can still get phone calls, FaceTime calls, text messages, alarms, and notifications.

Locking iPhone puts the display to sleep, saves the battery, and prevents anything from happening if you touch the screen. When you’re not using iPhone, press the Sleep/Wake button to lock iPhone. With this setting, you can control when you want the iPhone to go to sleep and your audiobook will not be interrupted. If I understand your question, when your iPhone screen goes to sleep (auto-lock is enabled), the audiobook that you are listening to turns off, is that right? One thing you can try is to set your Auto-Lock to Never to resolve this issue.

How to make iphone not sleep