Same Q here, I got Showtime to accept me and watching now, same with Starz, but HBO Max and Go and all of HBO refuses to allow me to watch using my Cox login pop up. I want to see season 3 of Westworld! :(
I could not log into the HBO websiteS, it booted me after the Cox log in screen. Same for the TV app. The preview is over now, but my working Showtime app has also now booted me, showing the Cox linking worked properly during the preview period for that provider, and Epix as well.
Are you trying to access the HBO Max app on Contour? If so, the HBO Max app is not currently accessible through the Contour box. For a list of devices that are able to view/stream HBO Max: https://bit.ly/3hUeQF0. If you have any trouble accessing that link, I've shared the below devices from HBO Max.
The following devices are supported by HBO Max. If a device is supported, you'll find the HBO Max app in the app store.
Amazon Fire tablets (4th gen and later)
Amazon Fire TV (with Fire OS 5.3.6 or later)
Amazon Fire TV Stick
Amazon Fire TV Cube
Amazon Fire TV Edition Smart TVs (Insignia HD, Insignia 4K UHD, Toshiba HD, Toshiba 4K UHD)
Android phones and tablets (with Android OS 5+)
Android TV (OS 5+)
Apple TV (4th gen and later)
iPhone, iPad, and iPod touch (with iOS 12.2+)
PC and Mac computers
Samsung TV (2016+)