Check the build log on sprintr.mendix.com → your application → Environments → Deployment packages. There will be a failed build waiting for you.
Sometimes there are build issues in the cloud. But I'm not seeing any issues at the moment on https://status.mendix.com/ .
You might want to try and create a deployment package from Studio Pro by hitting F7 or through Menu > App > Create deployment package. Maybe this fails too but it might give you more clues.