Zeptomail API (PHP) with invoice pdf attachment

Zeptomail API (PHP) with invoice pdf attachment

I am unable to properly make the syntax of API request via PHP to sent order invoice (PDF) in attachment. 

Below is my sample code API request - 
  2. $file = '169242759486.pdf';
  3. $attFile = 'https://www.example.com/secureInvoice/' . $file;
  4. $base64_attFile = chunk_split(base64_encode(file_get_contents($attFile)));
  5. "from": { "address": "sender@email.com", "name": "Sender Name"},
  6. "to": [{"email_address": {"address": "customer@email.com","name": "Customer Name"}}],
  7. "reply_to": {"address": "user@email.com", "name": "User Name"},
  8. "subject":"Test Email",
  9. "attachments": { "content": "'.$base64_attFile.' ", "mime_type": "application/pdf", "name": "myinvoice.pdf"},
  10. "htmlbody":"<div><b> Test email sent successfully. </b></div>",
  11. }'

I am getting the error response as - 

  1. {"error":{"code":"TM_3301","details":[{"code":"SM_101","message":"Invalid value format","target":"attachments"}],"message":"Bad Syntax"}}

Anybody kindly help me to fix it.