V1597757211521 , via OnePlus Nord , Feb 25, 2021 : There is a message being displayed at start up called error in application. Hopefully OnePlus will fix this issue
V1597757211521 , via OnePlus Nord , Feb 25, 2021 : It's coming as error in application immediately when I reboot or switch on my phone
Shailender Sharma , Feb 25, 2021 : Restart your device without sim card(s) once to ascertain whether the error is caused by sim card toolkit. If so, there is problem with the sim card.
V1597757211521 , via OnePlus Nord , Feb 25, 2021 : Thanks for helping. It's a problem with the airtel sim itself
V1597757211521 , via OnePlus Nord , Feb 25, 2021 : I cleared the cache and checked it's showing the same
Shailender Sharma , Feb 25, 2021 : Check with sim card other than Airtel, if the error in application again popping up.
Shailender Sharma , Feb 25, 2021 : So, replace the airtel sim from a nearest airtel kiosk or service center.