Q: Cannot add Family Member to Family Sharing

• Click on 'Add Family Member...'
• After entering their email, I am asked for my Apple ID password. 
• After entering password I click on 'Next' in top right corner.
• 'Next' turns into a spinny for a second then back to 'Next. 
• I never reach the next page and so can never finish getting the invite sent to family member.

Help!