The first thing to figure out is to make sure your AP11D has access to the Internet. LEDs on the device will provide a clue, as the internal web page of the AP, which you can connect to if you know its IP address. Even if your AP has been disconnected for a long time, it should reconnect. One thing you need to watch for though is the firmware upgrade which will take place the first time you connect it after a long down time. This firmware update can take easily 10 minutes or more after power up. During that time, you will not be able to setup the device.
If the above doesn't help to resolve your issue, you will likely need to contact Support. Keep us posted on your findings.