itunes cannot read the contents of the iphone 11pro max

Reboot computer and device, then try again. A potential fix given elsewhere is to remove a single song from the device then restart it which is supposed to rebuild the media database on the device.

tt2

Is all your media content available in iTunes to restore? When was your last successful backup to iTunes? Can you backup to iCloud as well for security? When exactly do you see this message, on connecting to USB, during backup, or when iTunes starts trying to sync?

One other thing you could try, see About the 'Trust This Computer' alert on your iPhone, iPad, or iPod touch - Apple Support and reset your trust settings.

Otherwise I suspect you're going to need to restore the device to factory settings and then restore your backup and reload your content.

tt2

Try https://appuals.com/fix-itunes-cannot-read-contents-iphone/. Not something I've personally run into.

tt2