Troubleshooting Autopilot enrollment error 0x81036502

When a computer is going through autopilot enrollment and throws error 0x81036502, the following can be used to determine the app causing the error:

When the device throws up the error, press Shift + F10 to open a cmd prompt. Open regedit.
Browse to HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\Autopilot\EnrollmentStatusTracking\Device\Setup\Apps\Tracking\Sidecar
Here you'll see all win32 apps being deployed. We only deploy win32 apps but you may have some other registry locations with apps in. You'll find them in this general area anyway.
Look for a registry value of 4. This app has failed installation is likely what caused the issue. Make a note of the app ID string.
Use the app ID string to go to the app in Intune
https://endpoint.microsoft.com/#view/Microsoft_Intune_Apps/SettingsMenu/~/0/appId/51ad2fef-6b6d-4eff...
I had to actually go in to the app, and visually find the app id, pasting it didn't work. I might have had an incorrect URL.
Anyway, that's how you find the app causing issues. Exclude it and you'll find ESP works fine.