why i cant't connecting with my wi-fi

[WPCentral Question]

I have a Lumia 540 that replaced my Samsung Focus. At my office we have Wifi available for guest and employees. The guest account is open and I have no problems connecting to it. However, the employees one will not connect. The access point is found and listed, I can click to connect and it asks for my credentials. After I enter them and wait a moment I always get a message that says "Connection unsuccessful: Your phone couldn't reach the Wi-Fi network xxx" Where xxx is the name of our employee wifi.