I'm using project collaboration (https://collaboration.dataminer.services/) to verify the status of my project but I don't see the closed tasks. Where can I find the closed tasks?
Ben Vandenberghe [SLC] [DevOps Enabler] Selected answer as best 24th September 2020
Normally you should be able to show the closed tasks on the List view (see screenshot below). You can do this by going to the Filter section and click on 'Looking for closed tasks?".
I was not able to view them on the current version of the platform. Maybe this is a software bug, however, when doing the same steps on the board view, it does work when you navigate back to the List view.
Ben Vandenberghe [SLC] [DevOps Enabler] Selected answer as best 24th September 2020
This is working for me. Maybe it was related to the higher number of closed tasks that had to be fetched in your case? 
Ben Vandenberghe [SLC] [DevOps Enabler] Answered question 24th September 2020