Can't Eject 2nd Tray in Mac Pro

I haven't been able to eject the second tray in Mac Pro.

The eject button and "option" + "eject" buttons on the keyboard both only eject the first or top tray in my experience.

In terms of troubleshooting, I've unplugged and then plugged the keyboard back in, and restarted the computer, but the problem with opening the second tray remains.
Note that this Mac Pro tower is new and I've only had it for a couple of days.

Thanks for any tips on how I can open the second tray.

Silly question and not meant to be patronizing, but did you order a second optical drive?

Not a silly question at all Kash - this happened recently when a client booked me to check his Win PC because, in his words, the "other drive door" doesn't open. When he'd bought the machine two weeks prior he hadn't specified that a second optical drive be put in! Readily remedied fortunately.