Nikon Z 7II User Manual page 707

D
Pairing Error
If you wait too long between pressing the button on the camera and
tapping the button on the iOS device, the device will display an error
message and pairing will fail. Dismiss the SnapBridge app and check
that it is not running in the background, then open the iOS "Settings"
app and request iOS to "forget" the camera before returning to Step 1.
"Forget" the camera using the iOS "Settings" app.
Connecting to Smart Devices
590