IOS file format corruption?

[michaelonz]

I am recording audio on both android and IOS and sending it to a webapi and saving it on a windows machine.
The recording from android records and plays back fine on android and on the webserver (via chrome).
The recording from IOS records and plays back fine on IOS but when i try and play it on the webserver it says the file is corrupt.
I have manually copied the file and it still doesn't work so I suspect the IOS device is creating a corrupt recording. I assume the file extension should be .wav on the server? Is anyone aware of any known problems transferring IOS recordings to a pc and playing them?