Carrie, did you try The Underestimated answer? I had the exact same problem as you, and when I checked the female connection on the wand it was badly clogged. Cleaned out, and my now works. Good luck.

Thank you everyone who posted - I used info from each! My Shark fell over, lost the spring and at the time was not even sure it was part of it. But door kept opening dumping all the debris out! I used a spring from a ball point pen. It didn’t fit over the “x”, but thanks to cup mention it positioned there and squashed down the latch. I also appreciate the flat screwdriver mention, otherwise I wouldn’t have gotten it off again. I am so relieved and appreciate all the thoughtful practical advice.