I have come upon a problem which only occurs on AT&T Wireless service (not T-Mobile), and may be related to UP.Link gateways and certain Web server configurations.
Getting an HTML or XHTML file will fail (getting a .GIF will not). The message displayed by the 3650 phone is "Missing Host Header".
The problem can be reproduced by going to www.mobile511.com from a 3650 using AWS service. (This site is hosted on Microsoft bCentral which is really an XO Communications service.)
I have included a link to an image of the cache file (from the phone's cache). Unfortunately, this behavior only appears on some IIS servers.
I have posted this problem several weeks ago on ATT Data Developer site with no resolution.
The version of the 3650 browser is:
Thanks for any help resolving this.