I have tried several different apps and always get an "authentication error", HTTP/1.1 401. I know that I put in a correct email and password. Is there a setting on the phone I need to change?
Have you verified that you are able to set up work email on a mobile device?
If this is a corporate email system, some companies set up mobile device management (MDM) using apps such as MobileIron or AirWatch and configure email that way. Other companies just don't enable Exchange ActiveSync (EAS) unless specifically approved. Your company should be able to guide you as to what you need to do.