Can't say, unless you share the file for analysis. Did the message say "codec is not supported?"
Upload the file/s to a free server, such as Google Drive or MS OneDrive, right-click the link and Share or Copy. Copy the result and paste it here or to me in a Private Message via the mail envelope in the top-right corner of this forum. When using Google Drive, click SHARE | SHARE and change "restricted" to "anyone with link can view.**