When running Time Attack sessions, it is possible that the following message may appear, indicating that the laps being run are unable to be submitted.
If you see this, the chances are good that your computer's clock is not in sync with the proper time for the timezone on the PC. In Windows 10 you can correct this by right-clicking on the clock in the task tray and selecting "Adjust date/time". In the page that opens up, either correct the time using the Change date and time option or toggle "Set time automatically" to on.
Once this is done and the sim is restarted, your (clean!) laps should be submitted for the Time Attack competition.