I cannot successfully send a second walkie-talkie invitation. The intended recipient does not receive the invitation

If you're having issues sending and receiving invitations

1. On your iPhone, open the Settings app and then tap FaceTime. Make sure that you're signed in with your Apple ID. Under You Can Be Reached By FaceTime At, make sure that your email address is selected. 
2. Restart your Apple Watch.
3. Restart your iPhone.
4. Try to send the invitation again. On your Apple Watch, open the Walkie-Talkie app, swipe left on the contact and then tap the delete button . Tap the plus button , then choose the same contact.