iPhone 11 Pro Max Volume Up button not working

take to store - or call support and they walk through trouble shooting

I had the iPhone 6 brand new first day out

after a couple days the power button broke

Replaced phone and a a couple weeks later the up volume broke & replaced phone

a few days later and the speaker broke

and after replacement a few days or so I had the ear piece go out

ALL different phones, SOME were replaced by my carrier at different stores and through apple via phone and different stores

I went through 5 phones

Then also had all kinds of other problems

finally the lady at apple store a manager gave me her personal phone and no problems

I literally got all the lemons

I should of played the lotto

Try a forced restart of you iPhone:--> Force restart iPhone – Apple Support

If you get no improvements, since your iPhone is brand new, have it inspected at an Apple Store or Authorized Service Provider, keeping also in mind that you have 14 days (from the date of purchase) to retun it or ask for a refund.

Regards

Giulio