I factory reset my XB8-t So that I could log in via the IP/ Admin page and enable UPNP but It says password or user is still wrong.

The default username is admin, and the default password is password, or it's the one that's written on the label on the bottom or back of the device.

@user_05n94a There was a recent update where you need to make sure that access to the admin tool is enabled in the app. For the login the username is admin and the password should be the one listed on the bottom of your modem. This article has more information for accessing the tool: 

https://www.xfinity.com/support/articles/admin-tool-access

Let us know if this helped at all or if you still cannot access after confirming these steps.

Darn echoes...............