Maybe you are turning off mobile data.
Always welcome, have a great day :)
I found brother, thank you
Dear OnePlus , firstly I would like to say Thank you for putting effort on OnePlus 7T pro that I just brought 1month ago and the phone is amazing....
actually my device is old .. so may be .. but I really like to use OnePlus.. with great experience.. camera is too good compare to Apple device,
Use a wired earphones.
On Setting - Network