If your SkyBell HD is solid green, or your customized color, it's in "Ready" mode but may not be properly sync'd to your account.
Please check to see if your SkyBell is synced to your account. If your device is not on your account, tap "Add Device" and follow the app syncing instructions which will begin by having you hold down the LED button on your SkyBell HD for roughly 45 seconds until it blinks red/green, which means ready to sync.