Invite friends and family encounters You can't make this change right now

I tried Firefox first which does not get to that page, but instead constantly letting me re-enter my account email and password, and confirm the service location (my address is the only one, I don't have multiple places), and then loop back to entering email and password. 

Then I switch to safari which gives me this "you cannot change..." page. I cleaned safari's cache and still the same. 

I don't use VPN.  

I can try clean up firefox's cache and see if it helps. 

Now clean up Firefox's cache and it behaves the same as safari. 

Thanks for trying all that!  Let me ask, have you tried adding them using the Xfinity App?  

I do everything on my phone and the App can do so much!  Can you give that a try please?  I am going to see what other solutions I may find.  Thanks so much for working with me!

I don't see the invite friends and family option on the app under account and identity... 
but at least it allows me to update phone number and email. I was not able to change phone number of email on the website. They also leads to "you can't change..." on the website when I am trying to update phone number or email. 

If you go to the account section once you are in the app, you should see Roles and Permissions.  When you click on that, something should pop up at the bottom, where you will see "add someone".  It will then ask you to verify your identity.   This will then take you to four steps, the first being "who do you want to add to your account?".  

Let me know if you see that on the app?  Thank you!