If your downloaded Google map shows streets but will not calculate a bus or walking route, the download may be working. The steps below refer to Google Maps on Android. Google documents that offline mode does not provide transit, walking or cycling directions. Re-downloading the same area will not add those modes. Google Maps Help: Download areas and navigate offline.
The immediate job is to separate a feature limitation from a failed download, then recover the information needed for your next journey.
Streets are visible, but the transit route is missing
Reconnect through a connection you can use and request the journey again. Before disconnecting, save the details you need: the stop name, route number, direction of travel, interchange and destination stop. A screenshot is a static reference, so record the travel date and do not assume it includes later disruption information.
For a short city trip, save one route back to your accommodation before exploring. Include the accommodation’s full address in a separate note. That gives you a recovery point if the map interface becomes confusing or your connection disappears again.
The map itself is missing or incomplete
While connected, inspect the downloaded area’s boundary and check that the download has completed. Google’s Android instructions place downloads under your profile and Offline maps; its help page also explains how to update them. Download availability can vary by country or region. Google Maps Help: Offline maps.
Do this before you depend on the map. Include arrival points and accommodation, not only the small central area where most attractions sit. Then test the display without a connection while you still have a way to fix it.
A driving route appears, but you are on foot
Do not follow it as a walking substitute. Treat its appearance as a sign to obtain a pedestrian route when connected, or use a verified local map and street information. A route calculated for a different mode is not evidence that its roads or crossings suit your journey.
If you cannot establish a route you are comfortable following, pause somewhere suitable and seek current local directions. Pressing on because an arrow exists is not a useful troubleshooting strategy.
A saved journey no longer matches the service
A screenshot cannot show a newly changed platform or cancellation. Consult the operator’s current information, station displays or staff before continuing. For a specific trip, save the official operator’s name and help page along with the route; this makes the next lookup easier without assuming Google’s cached information is live.
Build a small backup that answers the next question
You do not need a folder full of screenshots. For each important transfer, keep the start, destination, route, direction and a fallback contact or information source. For a hotel arrival, include the entrance instructions and check-in contact. Test that these notes are actually available offline. They serve a different purpose from the map: telling you what to do when navigation cannot calculate it.
Keep that recovery route in mind when choosing where to stay in a new city; an understandable return journey is part of a useful base.