need help please! email notification bar notification not working [yahoo / stock]

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http://forums.androidcentral.com – Hi all any help is appreciated and needed. I have tried to fix but cannot. My email notifications for yahoo [using yahoo app] or using stock email app [for yahoo] will not show the bar notification in the top notification bar. it worked for months now all of a sudden it wont. i have uninstalled/reinstalled the yahoo app it didnt fix i have deleted the stock account from the stock email browser it didnt fix it numerous restarts and battery pulls no go! anything else i can try? should I do a hard reset? thanks (HowTos)