Hello, I would be glad to assist you today. I am an avid BlackBerry user.
Can you please go to the "Manage Connections" icon, select that. Click on "Services Status" and tell me what that says.
Also, if you could go to the "Setup" icon and open the "Email Settings" app. This will show all accounts that are on the device and if there is a problem.
Have you changed the password XX your email account anytime? When the password XXX a synced email account is changed you must also update the password XXXX your BlackBerry device has stored for that account.