How to fix can't install app error 505 on a rooted device? I am on dirty unicorns 10.6 marshmallow rom. First I installed Gboard - Google keyboard app as system app through Lucky Patcher app. After restarting device I tried to open it through Lucky Patcher apps (There was no icon of Gboard app in my launcher) Launch App option but it didn't opened! So I uninstalled Gboard through Lucky Patcher. Then again I tried to install it normally through Play Store but I get this error 505 can't install app !! 
So there must be Gboard apps leftover files conflicting the apps installation now right ?
So how can I fix this ? How can I install Gboard app now ?
Note: I can install other apps without any problem !!!
That is because hide icon has been selected. Go to language and input tap the settings icon beside g board. From there go to advanced setting and tick show icon