Pairing problem with my Vivoactive3

I recently got a new iPhone Xs Max to replace my old iPhone 7. Things worked ok at first, but now when I try to use my Vivoactive 3 a 6 digit number comes up on the watch and a popup window comes up in Garmin Connect on my phone containing the following:
Bluetooth Pairing Request
"vivoactive3: would like to pair with your iPhone. Enter the code shown on "vivoactive3". Do not do anything on "vivoactive3" until pairing is complete.
Under this is a space to enter the code from the phone, but the phone will not bring up the keyboard to enter the number. Help!