I am trying to load my game onto the Google Play (Android Market). I used PhoneGap and download the .apk file. When I tried uploading it said "Google Play does not accept apks signed with the debug certificate. Create a new certificate that is valid for at least 50 years." So now I guess I need to make a certificate.
Did you follow the steps in this tutorial ?
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Did you enable 'debug mode' in PhoneGap Build's settings? That might have broken it.
Alternatively try creating an Android key in the Signing section of settings.