iOS - Playback failure from device filesystem

I'm having issues playing audio files from a local filesystem on iOS. Please see below for relevant debugging info...

**XCODE Output :**

```
2018-09-12 09:16:22.875388+0100 DK EFE[11346:64268] Will attempt to use file resource 'file:///Users/myname/Library/Developer/CoreSimulator/Devices/F7857F73-B645-42C2-8F2C-541E635F9163/data/Containers/Data/Application/D18F7ECE-1809-450B-A644-52E98CD49409/Library/NoCloud/audio/b1/c/3/b1_c_3_2_uk.mp3'

2018-09-12 09:16:22.875580+0100 DK EFE[11346:64268] Unknown resource 'file:///Users/myname/Library/Developer/CoreSimulator/Devices/F7857F73-B645-42C2-8F2C-541E635F9163/data/Containers/Data/Application/D18F7ECE-1809-450B-A644-52E98CD49409/Library/NoCloud/audio/b1/c/3/b1_c_3_2_uk.mp3'
```

**JS Console Output :**

```
{
code: 1,
message: "Cannot use audio file from resource 'file:///Users...'
}
```

Playback is successful when streaming via Cloudfront CDN but fails when attempting to load locally. The same application is running without any issues on Android.

The debugging output above is fro xcode but experiencing the same issues running application via TestFlight.

Any ideas?

The report provides Xcode and JavaScript console output for an iOS local MP3 failure, but names no repository file or test. Start by reproducing playback from the shown local filesystem path and compare it with the working Cloudfront case. Done means identifying and fixing the iOS local-file failure, with playback working in the application and TestFlight.

Written by the indexing model from the issue text.