I'm experiencing the same problem. Have already tried to reset password on web site, uninstalled app, reinstalled app, forced closed app, cleared data and cache. Yes 3G/4G is enabled. Always get error "Warning Username and password do not match." Any help greatly appreciated. Thanks, -Galaxy S 3 owner.
Chamberc, this situation sounds rather odd. The username and password you use on the website is the same username and password you should use for the app. When you try to connect to the app are you on wifi or 3g/4g? You must be on our network to connect through the app. Try connecting on 3g/4g and keep us posted.
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Chamberc, do you have more than 1 line on your account? If so, make sure you're using the user id/password tied to your S3. Also, try using your cell phone number for the user id and see if that works.
For some reason some users experience this hickup.. Some resolved with clearing cache for app so you may try that..
Go to Settings / Application/ Application Manager / My Verizon / Clear Data and then reboot and try again
Im having the same problem it says Username and password do not match. you pay all this money for verizon and get crap like this going on. do you think that VERIZON READ'S THIS STUFF? if not they should and try to fix what's going on.