This.outlet is undefined error after upgrading to Ionic 5

Hello ,

After upgrading to Ionic 5 ,
I am getting the issue when i try to open my project in Firefox

Error: Uncaught (in promise): TypeError: this.outlet is undefined

and in chrome

TypeError: Cannot read property 'getActiveStackId' of undefined
    at IonTabs.push../node_modules/@ionic/angular/fesm5/ionic-angular.js.IonTabs.getSelected (ionic-angular.js:3090)

and below are some of the dependencies and the versions i have in my package.json

@angular-devkit/build-angular”: “^0.803.25”,
@ionic/angular”: “^5.6.9”,

Angular version 8.x

Any suggestions on what can be done?