Troubles running the Walkie Talkie app

My wife and I just purchased and set up our Apple Watches (series 4). We are having trouble running the Walkie Talkie app....will not send invitations, nor recognize each other as even having Apple Watches. FaceTime is correctly set up on each iPhone and attached to the email addresses used for apple ids. We have restarted both the watches and the phones; all are updated to the most recent operating systems. Please advise. Thank you.

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