My APK downloads ok with the Companion but won't install on phone

Has anyone been successful lately in sideloading their app to Galaxy S10+? I have successfully sideloaded apps before generated on other IDEs, however apps generated on Appinventor always return "unnable to install."

Two possibilities:

  • wrong app icon size or type
  • failure to insist on install when confronted with warnings about not coming from the Play Store

Thanks, kicking myself over the whole not giving the app an icon thing.