Blocking of unsanctioned apps

Hello guys,

I'm just getting started with Microsoft Defender for Cloud Apps but have already worked a bit with it when it was still named Cloud App Security. Right now, I'm looking into the Cloud Discovery features. While trying out the Unsanctioned feature for some apps, I ran into the problem that they only get blocked if the user is using Microsoft Edge. If the user uses Chrome or Firefox, the app doesn't get blocked. I integrated MDCA with Microsoft Defender for Endpoint. What am I missing?

Best regards

Salomo