Navigation works with GPS.
There is no GPS signal inside the tunnels (as well as inside the buildings).
Phones can only communicate with satellites when they are outside.
It is recommended to disable the automatic rerouting.
Try another “Location service” or “Kalman filter” in location settings.
- How and why can I navigate with manual rerouting? [Kurviger Knowledgebase]
- Wie kann ich mit manueller Neuberechnung fahren und warum? [Kurviger Knowledgebase]
See also here: