This post has been escalated to our Support team. If you have a similar question please submit a support ticket and we will investigate further.

UPDATE FROM SUPPORT:  The error message we are seeing on our end is "The upload appears to be malformed and we are unable to process it." The best option is to reach out directly to the 3rd party app to see if they can look into any file errors. You may be able to try stripping different data from the file using Fit Tools - Field Stripper, as one of those fields is typically the culprit to the error message. Otherwise, you do have a couple of good options for getting credit for your efforts.
 
1. Manual Activity

• You can create a manual activity to account for the lost mileage - although this won't count toward Strava Challenges and won't match to any segments.

For more information on how this feature works, please see the help articles for web, iPhone or Android.
 
2. Activity sharing: If you were with a friend who recorded the activity with GPS

• If you were with another Strava user, that friend can share their activity with you. You'll need to ask them to use the Add Friend button on their activity detail page which will allow them to share the activity with you. Once they've sent the invitation you can accept the copy of the activity as your own. If you accept the invitation, your friend's activity will appear on your Strava profile and feed as if it was your own. You will be grouped with the friend who invited you, the activity will count towards Challenges and Clubs you are a part of, and the activity will count towards your personal stats. The activity you're tagged in will not count towards segment leaderboards, running estimated best efforts and won't include heart, power, or cadence data.

For more information on how this feature works please see our Help Center article.