Google Maps, Try Again in a Few Minutes
Android 7.0 (patch Oct 5, 2016) Maps abruptly can not Locate current position when Routing new Destination. - Solution (Google patch "disables" > Settings - System - Date & time - Automatic date & time ) slide to turn it green to "Turn it Back on!!!" after a few seconds it can calculate GPS coordinates again.
A symptom or "work-around" for this is you can select your Location [ manually ] by tapping the Location box before pressing [ Route ] and choose to Pick your current location from a map, then press the GPS coordinate locator.. which uses the [ very same function!! ] and then it returns you to the routing screen and you can press [ Route ] and it will work.