You are maybe getting some issues while trying to connect Qobuz to Soundiiz.
Be sure to logout from Qobuz website before connecting Qobuz to Soundiiz. Go on https://www.qobuz.com/ and logout from your Qobuz account.
Once that done, go back on Soundiiz, select "Qobuz" and enter your Qobuz credentials. You will get a success Qobuz message after that and the popup will be closed by itself.
That should be good ! If you want to use another Qobuz account, be sure to disconnect it from Soundiiz and again, logout from Qobuz website first. Then go back to Soundiiz and repeat these steps.