Mobile data not working with certain apps

1. Is this your corporate iPhone? Then please contact the system administrator of your corporate
2. If it is your personal device, in that case, do you have any profile installed by your corporate/organisation/enterprise/School Management?
   1. Erase the profile added by you If you have installed a profile on your own --> Install or remove configuration profiles on iPhone - Apple ...
   2. Or please contact the system administrator of the organisation who provided the profile to you

Try a Reset All Settings (No Data is Lost)

This resets all your personalized features back to factory defaults

Go to Settings > General > Reset > Reset All Settings

• What this effectively does is to reset some of your Settings to factory default. It’s not a complete removal of settings. It removes all of your preferences for Wi-Fi, Bluetooth, Do No Disturb, Notifications, General, Sounds, Brightness & Wallpaper and Privacy.
• Resetting all settings also reverts all your personalized and customized features like wallpapers and accessibility settings back to factory defaults.
• Performing this action does not impact any of your personal device data, including photos, videos, notes, messages, reminders, emails, calendars, texts, documents, and other files