Uploading audio files breaks sometimes

Two of four of my most recent music uploads have had to be refunded due to “being unable to open the file(s)”
I’ve opened the files in various applications and they worked fine. So this must be an error with reviewing files or issues when uploading to the website. (If I played the non-reviewed audio in a place in studio it worked fine. But I don’t know if this occurrence is using a version of the file stored in my client or in the server)

The files I uploaded have all been in .mp3 format.
I don’t have anything else to provide beyond that. Thank you for your cooperation.