A recent update to Google Maps for Android seems to have broken the map for some users. I’m working on a fix but in the meantime you can follow these instructions to get it working again…
Open the Google Play Store and search for “Maps”:
Find the Google Maps application and click on it:
Now click “Uninstall” – on pre-loaded phones this will just remove the updates and not the application itself:
Open it and try Open Canal Map for Google Maps again.