Ok this is really weird. I tethered my laptop to my ATT Note 3 that is on Tmobile service using Es File Explorer net manager settings app. I went to google.com and did NOT get an upsell message. I went to yahoo.com and did receive an upsell message. How strange? I tested a few other websites and it appears tmobile blocks some websites and it doesn't block others. I have a VPN, so I turned it on and now I can surf any website. Thanks for the tip wally3614.