If you have "red message indicator" in couch to 5k/5k to 10k app as below and need to remove/clear it, please refer to the following steps:
User-added image
  1. Open app
  2. Go to Settings
  3. Tap Sign In
  4. Sign in with ACTIVE.com account information
  5. Tap Sign In again
  6. Go to Community
  7. Tap ring bell/News button at top left corner
  8. View message