Ionic iOS request to API gives sometimes error unknown, status 0

I have a Ionic 4 with Angular app which connects to my API. On Android / Browser the calls to the API are working (no errors on the console). However on iOS I sometimes get an error “status”:0,“statusText”: “Unknown Error”

"statusText": "Unknown Error",
"message":"Http failure response for 0 Unknown Error",

the weird thing is, this is not happening all the time.


  1. Angular httpClient GET call to => Works, getting data back
  2. Another GET call (navigation occured) to => Works
  3. Going back to previous page a new GET call to fails and throws above error.

It doesn’t matter how many times you navigate, it randomly throws the above error. If it had anything to do with CORS I assume it would throw the error everytime you do a request on iOS.

Ionic info


   Ionic CLI                     : 5.2.7 (/usr/local/lib/node_modules/ionic)
   Ionic Framework               : @ionic/angular 4.8.1
   @angular-devkit/build-angular : 0.801.3
   @angular-devkit/schematics    : 8.3.2
   @angular/cli                  : 8.3.2
   @ionic/angular-toolkit        : 2.0.0


   Cordova CLI       : 9.0.0 (cordova-lib@9.0.1)
   Cordova Platforms : ios 5.0.1
   Cordova Plugins   : cordova-plugin-ionic-keyboard 2.1.3, cordova-plugin-ionic-webview 4.1.1, (and 10 other plugins)


   cordova-res : 0.6.0 
   native-run  : 0.2.8 


   ios-sim : 8.0.2
   NodeJS  : v10.16.3 (/usr/local/bin/node)
   npm     : 6.9.0
   OS      : macOS Mojave
   Xcode   : Xcode 10.2.1 Build version 10E1001

Safari console screenshot:

No one experiencing this issue ?
I reduced the API calls, but still now and then I get this error.