You don't receive any voice navigation?
This could be because you upgraded your operating system.
In this case, please reinstall Google Text-to-speech. You can find and reinstall Google Text-to-Speech via the Google Play Store. After installing the app, you need to activate the app in the settings (Profile (Head Icon) -> Settings (Cogwheels Icon) -> Navigation).
It might also be necessary to log out of the komoot app. Once you have done that, start another tour - you should be able to use your voice navigation again.