I Tried To Tag With My Child, But When I Pressed the C1 button It Showed Out Of Range

The best way to fix it is to slow down to be within the 40-meter radius before pressing the C1 button on-screen. You will need to ensure you do not step out of the range of the virtual tag before pressing the C1. If there is another tag within close proximity, it may sometimes interfere depending on if you ever exited the tag range that was scanned by your main account and entered the range of the new tag waiting to be scanned by your main account, pressing the C1 at this point will be unresponsive.