hi, i apologize in advance if i posted this in the wrong place, i have a friend that has comcast as their isp. about 5 days ago their email stopped working, when they contacted comcast support they were told their email address don't exist and never did exist, so the tech recreated their emails and he was able to logon one time but after that he only gets an error message stating

HTTP ERROR: 400

invalid request: server abs.comcast.net does not have zimbraMailMode set, maybe it is not a store server?
RequestURI=/service/preauth

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he has tried logging on from all his pc's at home, i also get this message when logging on from my work, and the comcast tech gets this when trying from their side. i'm sure after researching around that this is something related to a setup issue on comcast's side, which doesn't surprise me. and of course their stumped. what i'm looking for is a more technical explanation of the fix or other wordage that i can give him so he can call comcast and get someone to fix it that knows what their doing. the site that their webmail login goes to is http://smartzone.comcast.net, he also has tried it through a mail client with no luck. thanks for your time