Hi I have done some reaserch on this issue and I do not think it is directly connected to Firefox Focus for Android, but I think I might be able to help. # Open the '''Settings''' menu on your device. # Go to '''Apps''' or '''Application Manager'''. (This option might differ depending on your device.) # Scroll to '''All apps''' and then scroll down to the '''Google Play Store''' app. # Open the app details and tap the '''Force stop''' button. # Tap the '''Clear cache''' button. # Repeat the steps above, but replace Google Play Store in step 3 with '''Google Play services'''. # Try to download the app again. (Taken from this [https://support.vitalsource.com/hc/en-us/articles/222788768-Resolve-app-installation-errors-in-Google-Play-Store?mobile_site=true page].) I hope that this helps.