I'm unable to add more family members when the "Add Person" button is not working?

In family sharing my add person button is grayed out. I only have 4 family member which includes myself. I am allowed to have up to 6 but it will not let me add anyone else. I have tried logging out and logging back in. I know how to add a person obviously but it is no longer giving me the option even though I should be able to add 2 more people.

[Re-Titled by Moderator]