Ionic blank when restarting app

Hello! I have a app made in Ionic 3.
The app has been in AppStore and Google Play for a couple of months and I’ve never had any problems with it. However from yesterday I have a big problem.

When i start the app i get the ionic blank template (the world is your oyster…)
When I delete the app and reinstall it it will work the first time and then when I restart the app I get Ionic blank and have to reinstall it again.

I do not use Ionic Pro and auto deploy/update.
I do not have any code in the whole app folder that has the ionic blank text: the world is your oyster… So it has to be getting the page from another source than the app build itself.
I do not have any builds or channels on Ionic Pro website either.

The problem just came by itself. During it’s four months online I’ve never got a single error feedback. Today I got over a hundred people reporting this problem.
I’d update ionic and cordova and then push a new update to the stores however I’m on vacation and I can’t even try that solution.

Steps again:
Install app.
Start and use app perfectly.
Close app.
Start app and get ionic blank forever until reinstall.

Has anybody had a similar problem or has an idea what the problem might be?
Thank you in advance.