I have Samsung Galaxy mini 4. Have not received any new emails for 5 days. this problem has happened a few times. When I went to the store they had to uninstall my email (optonline) then reinstall. How do I uninstall it?
If you use the default stock email app: Go to settings-accounts-tap your email account-tap menu-tap remove account. Then, go back to the main accounts screen and tap menu-add account.
If you use a dedicated email app like Outlook, Yahoo, Gmail, etc....you can remove the account from the app or delete the app altogether then readd the account or the app.