Gasket and ring on bin

Did you try removing the bin completely to put it back in place? There is a small red tab on the bottom of the canister that you push in and the entire canister slides off giving full access to all the gaskets.

I have this problem as well. The clips that hold the plastic ring in place broke in the process of opening and closing the canister. I have just spoken to Dyson support. The closest thing to the part available for purchase on their website is this: https://www.dyson.com/support/journey/sp.... They informed me that the entire canister needs to be replaced at a cost of 30$ plus shipping--not worth it for such a small part. Images below for reference.