Unable to add second user to Xfinity account.. They get error every time they try to Set up account with their login

My fiancé and I are trying to make it so that we both have access to our Xfinity account, We both have for access and management abilities of our account. I am the primary account holder and the Internet was set up in my name two years ago. However, we are trying to Make it so that we both have full access to all of our utility accounts and servicers So that we are not having to worry about it immediately after our wedding.. 

We have tried this, probably more than half a dozen times.. I put his name his email and his phone number, I submit The information And he receives the text and email invitation immediately from Xfinity.. he is He will open the “get started” Hyperlink from both his text messages and from his email.. Xfinity app opens And depending on which link was used , He’s prompted to either confirm his email address or phone number.. He is able to The correct information, And each time This prompts a six digit code to either get sent to his email address or text messages. But every single time the six digit code Is used and We go to validate His credentials, He instantly gets an error which is the same every single time, “ That didn’t go as planned” Please try again later. We have tried refreshing the page, Reopening the invitation link before it is expired, I have tried removing the invitation request so I can Retype in his name And credentials to send a new invitation.. But each Thing we have tried, he gets the exact same error at The exact same step in his registration process.. So he has not Been able to Validate his identity and has not yet been asked to create a password.. We even tried To go through this process using my phone instead Since my abs seems to be working fine But the same thing happens.. We both have iPhone 15 Pro maxes, And are on the same Wi-Fi.. Can someone tell me why he is not able to join our account and why we are continuing to get this error??