Copy the below url and open it on your phone browser and complete the Strava login.
https://www.strava.com/oauth/authorize?client_id=11688&response_type=code&redirect_uri=http://www.mibandnotify.com/sync/strava/oauth.php&scope=write&state=myState2&approval_prompt=forceOnce finished you will see something like this
Success 27d4ef8ffc8d23452bxxx084a9e1716abe00xx29
Copy your code showed after Success (without any empty space) here