Why is the canister loose?

It sounds weird but is there some debris blocking it from fitting properly? Have you placed the filter the right way around? I do not own one of these but i had this problem with a vacuum i have used. Hope it works!

I have a similar problem that I have resolved. My dustbin canister also seemed too low to align with the ports and the latch. I've since learned that there's a plastic piece on the top of the canister that has broken off. One option is to replace the canister top. I found another solution that seems to be working just fine. I inserted a shim between the hepa filter base and the bottom of the canister, about a quarter of an inch high. That seems to have solved the problem. If it's not satisfactory, I will buy a replacement top. Good luck.