Buzzing/hissing/white noise with MYO cards

Hi all,

Just wondering if anyone else has experienced this and knows a fix? I've brought a pack of official MYO cards and been making the Harry Potter books for my kids with files taken from my audiobook accounts. 6 out of the 7 books work absolutely fine and sound perfect, but book 5 (order of the Phoenix) has a buzzing/hissing/white noise type sound constantly whilst playing from either the card or remotely from the app. If I play the files from the app on my phone or on my PC, the sound is perfect. I thought it might be due to the file type, so I have tried mp3 and m4a. Also tried making the playlist with 2-3 chapters in case the 39 chapters (29hours) were too long, but still the noise is there. Even having the playlist fully downloaded to the device, does not help.

Any ideas will be greatly appreciated.

UPDATE I did as ScrandyPK suggested and re-uploaded the files and the buzzing has gone. Seems they have fixed the issue on their end.

Thank you all for the suggestions and help.