You uploaded new app bundle to update my publication and got the message To upload an Android bundle you must be enrolled in Play App Signing. In that case there should be a message like this at the top of the page: 
We have a fix for that. Please go to your Dashboard and select an app you're trying to update: 
After that please click here and follow our step-by-step guide to get your App Signing Private key.
❗️ Important ❗️ Don't forget to double-check that you selected the right app before taking any steps:
