Is a default navigation app already set on your device (for example Google Maps)? You can change this as follows:
Android
Go to Settings → Apps → select the navigation app (e.g. Google Maps) → Open by default → Clear defaults. The next time you navigate from Campercontact, you can choose a different app and set it as default if you wish.
iOS (iPhone)
On iOS, it is not possible to set a default navigation app. However, when starting navigation in Campercontact, you can directly choose from the available apps, such as Google Maps or Waze.