An unwanted emoji is showing up in Slack messages sent through to webhook – Shopify

I’ve searched everywhere to find someone else with this issue but couldn’t find anything.

The issue is I am trying to send a message from a php script to my slack channel with the Shopify order number. It’s working as it should apart from one thing, It’s adding a Red Square emoji in the messages and I can’t figure out why.

This is what the message comes through as:

red square that shouldn’t be there

And this is the code I’m using to send the slack message:

  // Create a constant to store your Slack URL
  define('SLACK_WEBHOOK', 'https://hooks.slack.com/services/x/x/eActr8MIhT0SIyKuGGwR0ScU');
  // Make your message
  $message = array('payload' => json_encode(array('text' => 'Order '.$shopify_order['name'].' has been sent to Embroidery Works' )));
  // Use curl to send your message
  $c = curl_init(SLACK_WEBHOOK);
  curl_setopt($c, CURLOPT_SSL_VERIFYPEER, false);
  curl_setopt($c, CURLOPT_POST, true);
  curl_setopt($c, CURLOPT_RETURNTRANSFER, true);
  curl_setopt($c, CURLOPT_POSTFIELDS, $message);
  curl_exec($c);
  curl_close($c);