I like the statement "Sipmly shows DHCP Discovery"

I fact there are multiple layers of infrastructure involved into the process.
The reason for this message is that the phone cannot obtain an IP address. If someone else does manage your network, I'd recommend to invite them. If you do it yourself, then you should be able to do next simple steps.
1. Physical connectivity. Connect a computer to the cable and make sure you see ethernet link lights on both switch and network adaptor.
2. If you don't have voice vlan, and your computer set to use DHCP, then it should obtain an IP address.
3. If you do use voice vlan, then things getting more complicated and you need to check CAM tables (MAC address tables) on your switches.
4. Make sure that DHCP process is running. Connect a computer to access port of your voice network and confirm that you got an IP address.
5. If nothing helps try to set your phone to static config. Use button "2" features.
6. If your computer can obtain an IP address and the phone cannot, check connector pins in the phone. Try to connect a computer in aux jack on the phone. Are you able to get connected from there while the phone is discovering DHCP.
And so far so on...