The application cannot be opened without a wifi connection. It gives an error. What is the reason I cannot use it with internet connection?

Check your settings to make sure Cellular Data is enabled for the app. This article may help:

https://support.apple.com/guide/iphone/view-or-change-cellular-data-settings-iph3dd5f213/ios

some of my apps are not working with my mobile data even if i am having enough data balance i checked this option cellular data is already enabled still my apps are not working i have to use my home wifi for that particular apps

I have the same problem. I’ve Tried deleting app, and downloading it again. Tried resetting my phone settings ect. The app still won’t work on mobile data. Only wifi.