How do I fix black screen issue on iPhone 16 Pro Max?

First try a Forced Restart to determine if this is a software issue.

Force restart iPhone - Apple Support

If that doesn’t fix it, this is likely a hardware issue that needs service attention at your nearest Apple Store’s Genius Bar or Apple Authorized Service Provider. You are still within the 1 Year Manufacturers Warranty which covers defects if that is determined.

Genius Bar Reservation and Apple Support Options - Apple

I know you said you purchased it three weeks ago. If you noticed it two weeks or earlier, you should’ve returned it for a full refund from Apple.

NatalieGol27 wrote:

I recently purchased an iPhone 16 Pro Max (about three weeks ago), and I’ve experienced a recurring issue: the screen suddenly goes completely black, while the phone itself continues to function — I can hear sounds, receive calls and notifications, but nothing is displayed, and the screen doesn’t respond.

The only way to temporarily fix it just to wait 20-50 minutes. This has happened three times already. The phone has not been dropped or exposed to moisture.

Could this be a hardware issue? Should I bring it to a service center for diagnostics?

click here If your iPhone won't turn on or the screen is black - Apple Support