A session that's been just finished in the simulator or recently imported, and is shown shaded in gray in your history, it is being processed in the system.
Usually sessions are processed in a few minutes, but at times of high load, it can even take a few hours. It is not a system failure. If the activity had not been processed after 24 hours, please contact us.
If you have synchronized your sessions with Strava, this will happen once the session is processed, and always, at the rate indicated by Strava.
You can find your sessions in "My activity> History".