google maps not showing the routes

Hi,

I have an iPhone 6 with ios11.2.6 . I have a problem with google maps: I choose a location on the map and then touch directions button to see the routes. but the top toolbar that shows the beginning and destination only appears for less than a second and then disappears and the map only shows beginning and destination spots on the map without any route between them.😕 I think I have faced this since I upgraded ios to version 11.

I have tried uninstalling and reinstalling google maps, resetting location service and even factory reset but the problem not solved.

please someone help me to fix the problem.

Thanks