Error Signing In - There is no connection to the Internet
I'm trying to add an Exchange/Office 365 mailbox to a users iPhone X. When i get to the part where i'm prompted to sign in (iphone screen text: "Sign in to your 'company.com' Exchange account using Microsoft? Your email address will be sent to Microsoft to discover your Exchange account information") i get an error message after tapping 'sign in' that says "Error Signing In There is no connection to the Internet." I did verify that the phone does have Internet access, plus when we installed Outlook Mobile on his phone there were no issues configuring it using auto discover.
It's the same result whether wifi is on or off, cellular data or no cellular data.
If it weren't for the "no connection" error, i'd say this was probably an issue with his account, or something on Microsoft's end. But obviously there's something else going on here that seems specific to the phone. I've configured multiple other iPhones using this method without issue, but i'm not sure if any of them were the "X" model.
Btw, if i configure his account manually the mailbox setup works, but because of the companies security settings the connection is blocked. It has to happen via the auto discover process (i.e. tap "Sign in" instead of "Configure Manually".
I've attached the relevant information. Hopefully someone has seen this before and can point me in the right direction.
Thanks in advance.