Hey @JA56_2, 
Thanks for your post. Please try our initial troubleshooting step of deleting and reinstalling the Strava app. Our recommended instructions are below:

1. Delete the Strava application from your phone
2. Power your device off for 10 seconds
3. Turn your phone back on
4. Reinstall the Strava application 

Note: You will not lose any data if you do this since all data is stored on the Strava servers.

Google Play Store:
Strava: Track Running, Cycling & Swimming
How to update your apps on Android: Support - Google

Apple App Store:
Strava: Run, Ride, Swim
How to update your apps on Apple: Support - Apple

If you have issues after doing the above, please submit a support ticket and our support team will further assist you.