Play Store error -507: What does it mean?

I’ve built a very simple app with ionic and submitted it to the Google Play Store for alpha testing. When I’m trying to install the apk from the store on the phone I get an error message that says “Couldn’t install, error code -507”. Does anyone know what that error code means?

The only thing I could find was this SO-thread: Don’t think it helps me though.

Turns out I was requiring a preview android api version that was not released yet.