Mail API Get Email Attachment Content Returns HTTP Status 406

Mail API Get Email Attachment Content Returns HTTP Status 406

Hi,

I am trying to get the email attachments via the Mail API (https://www.zoho.com/mail/help/api/get-attachment-content.html) in PHP using CURL. I am able to get the Email Content and Attachment Info (https://www.zoho.com/mail/help/api/get-attach-info.html) but when I try to get the attachment content via the https://mail.zoho.com/api/accounts/{accountId}/folders/{folderId}/messages/{messageId}/attachments/{attachmentId}
 Request URL, the response I am getting back is:

<!doctype html><html lang="en"><head><title>HTTP Status 406 \xe2\x80\x93 Not Acceptable</title><style type="text/css">body {font-family:Tahoma,Arial,sans-serif;} h1, h2, h3, b {color:white;background-color:#525D76;} h1 {font-size:22px;} h2 {font-size:16px;} h3 {font-size:14px;} p {font-size:12px;} a {color:black;} .line {height:1px;background-color:#525D76;border:none;}</style></head><body><h1>HTTP Status 406 \xe2\x80\x93 Not Acceptable</h1></body></html>

Thank you in advance for any assistance.
Kelvin