Just a few hours ago, Epic Games released Fortnite Update v5.21. Shortly after the patch 1.71 was ready for download came first error messages from Android players.
In the official Fortnite forum it has now been announced that there are problems with Update v5.21, if you want to update your Android version. There is still no solution to this problem, but it is being investigated at the moment.
The problem should be fixed soon, we will inform you if there is news!
All details about Fortnite Update v5.21 can be found here.