Why mu iphone send a mobile data update error ?

Hey there Salman_h,

Welcome to the Apple Support Communities!

We see you're having an error message appear on your iPhone 11 stating that the mobile data update failed. This can happen if the carrier update was not included in the iOS update in your region, or there was an issue while it was trying to connect and update to the carrier.

One way to resolve this is to attempt to manually update the carrier settings with the steps here:

Manually update your carrier settings on your iPhone or iPad - Apple Support

From there, in the article you were originally viewing, you can find more steps to help like connecting your iPhone to a computer under "What to do next":

If you see an Update failed or Apple Pay Not Available alert after iOS update or restart - Apple Support

These steps should get you back to being able to use your iPhone, but you might also check with your mobile provider to make sure your account is active.

Have a wonderful rest of your day!

Cheers!