How do I fix sound volume issue on my iPhone 12 Pro Max?

Hello!

Head to: Settings > Sounds and Haptics. Now, ensure the slider is dragged all the way to the right:

Then head to: Settings > Focus, and make sure it doesn’t say “on” next to any of the Focuses:

Lastly, make sure the top switch on the left side of your iPhone is black, and not orange, or, if applicable, make sure the Silent Mode bell in Control Center is not red & white but rather as the one below:

Let us know if the issue persists. Have a great day!

Try to go to settings, then sound. Make sure the ringer is high. Maybe restart phone?