Hello Irina,
I am not sure about the issue you are seeing so I reached out to someone,
He recommends making sure you created a new Junos Genius account at www.junosgenius.net and that you download the new version of the app. If so, you should be able to access the JNCIA-Junos practice tests that are in the new platform--the easiest was to do so would be to search on “JNCIA”.
I hope this helps and that you are doing well. Thanks for participating in the forum.
Gordon