Blinking green power light on Aruba hardware indicates that it's booting up or syncing the config from the cloud - And a single boot cycle on these can take almost 10 minutes on the AP11D. Now that V2 is released and most of the inventory that's shipping is still flashed with V1, it's entirely normal for that device to take 20 minutes out of the box to be ready to dance, because it has to boot up, phone home to the cloud, download the new firmware, reboot, then phone home again. During this entire time, the HTTPS won't be available. And if the process is interrupted, it usually has to start over.
If you get your hands on a console cable (Aruba AP-CBL-SERU, JY728A) the port is on the back and looks like micro-USB (it's not), you can at least see what's happening on the console - if it's just sitting there or actually doing something (although to my knowledge, once it's booted, there's no way to actually log into the CLI unless you're TAC and know the secret handshake). Caveat: the other APs have a different console connection and require a different cable.