Can anyone help me fix my corrupted .fit file

This will work - [solved]

It looks like timestamps stopped recording around 1 hr 26 min into the ride, then picked up again around the 2-hour mark.

Not sure if you physically pressed the start/stop button to stop recording or if there is an issue with the watch. Maybe this was a planned stop? I would use the "resume later" option if it is an extended stop. At any rate Fit File Repair Tool is able to account for this and make the file acceptable to Garmin Connect.

antbarrett said:

prevent the problem from happening again?

No guarantees, but I would make sure of the following, at least before your next ride:

• Sync your device then remove all activity fit files from your Garmin device using these directions - Removing Recorded Activities on a Garmin Fitness Device 
• Check for firmware updates using Garmin Express
  

• Also, note that HRM-Pro, Pro Plus, Tri, and Swim will sometimes corrupt activity fit files 

  • Use the HRM download feature only after an activity where it was not possible to wear the watch
  • Update the HRM firmware Updating Software on the HRM-Pro/Pro Plus
  • During the HRM-Pro download process keep the strap and watch in close proximity
  • If issues persist even after the firmware update, contact Garmin Support
  • More here about corrupted HR data: Corrupt FIT File Repair Requests