If your map does not rotate when you toggle the map screen crosshair button to "green", first refer to our guide: Make the Map Orient to the Direction of Your Movement and Scroll As You Move .
If it still doesn't work, the problem may be caused by your "Compass Calibration" System Services being denied access to Location Services. This setting is enabled by default, so it's rare that someone would disable it, but nevertheless if it happens, here's how to fix it:
On your iPhone / iPad, open up iOS Settings and tap Privacy:
Then tap Location Services:
Now scroll all the way to the bottom, and tap System Services:
Now check that your Compass Calibration is enabled. On 99% of devices, your screen will have everything enabled like the following screenshot:
This should solve your map orientation issues. If the issue persists, please contact support (see sidebar).