Ionic 4 Upload Error

I updated my app to ionic 4, did some changes and wanted to upload it to the iOS AppStore. PlayStore worked fine but the AppStore is creating an error message

Upload failed

App store connect operation error
Your app contains non-public API usage. Please, review the errors, correct them, and resubmit your application.

App store connect operation error
The app references non-public selectors in Payload/

I tried

cordova plugin rm cordova-plugin-ionic-webview
cordova plugin add cordova-plugin-ionic-webview@4.1.0
npm install
ionic cordova build ios --release

as it was mentioned here: but it didn’t changed anything.
I tried renaming _setAlwaysRunsAtForegroundPriority which fixed the upload error but caused a crash after startup (Signal SIGABRT).

Do you have any suggestions what I can do?
Thank you very much