function create_contact() {
 $curl = curl_init();
 $url = "https://api.sendgrid.com/v3/marketing/contacts";
 curl_setopt($curl, CURLOPT_PUT, 1);
 curl_setopt($curl, CURLOPT_URL, $url);
 curl_setopt($curl, CURLOPT_RETURNTRANSFER, true);
 curl_setopt($curl, CURLINFO_HEADER_OUT, true);
 $apiKey = 'Bearer SG.MyAPIKey';
 curl_setopt($curl, CURLOPT_HTTPHEADER, array(
 "Content-Type: application/json",
 'Authorization: ' . $apiKey,
 'Expect:'
 ));
	$data = <<<DATA
	{
	 "contacts": [{"email": "tp302.tp302@gmail.com"}]
	}
	DATA;
 curl_setopt($curl, CURLOPT_POSTFIELDS, $data);
 //for debug only!
 curl_setopt($curl, CURLOPT_SSL_VERIFYHOST, false);
 curl_setopt($curl, CURLOPT_SSL_VERIFYPEER, false);
 try {
 $resp = curl_exec($curl);
 $result = json_decode($resp);
 var_dump($result);
	
 } catch (exception $ex) {
 
 var_dump($ex);
	
 } finally {
 
	 $info = curl_getinfo($curl);
	 var_dump($info);
	
	 curl_close($curl);
 }
}

# paste exception/log here
Here is the info returned from curl_getinfo():
array (size=38)
 'url' => string 'https://api.sendgrid.com/v3/marketing/contacts' (length=46)
 'content_type' => null
 'http_code' => int 0
 'header_size' => int 0
 'request_size' => int 221
 'filetime' => int -1
 'ssl_verify_result' => int 19
 'redirect_count' => int 0
 'total_time' => float 60.078775
 'namelookup_time' => float 0.034369
 'connect_time' => float 0.045485
 'pretransfer_time' => float 0.068833
 'size_upload' => float 0
 'size_download' => float 0
 'speed_download' => float 0
 'speed_upload' => float 0
 'download_content_length' => float -1
 'upload_content_length' => float 54
 'starttransfer_time' => float 0.068838
 'redirect_time' => float 0
 'redirect_url' => string '' (length=0)
 'primary_ip' => string '54.213.76.12' (length=12)
 'certinfo' => 
 array (size=0)
 empty
 'primary_port' => int 443
 'local_ip' => string '192.168.1.133' (length=13)
 'local_port' => int 50342
 'http_version' => int 0
 'protocol' => int 2
 'ssl_verifyresult' => int 0
 'scheme' => string 'HTTPS' (length=5)
 'appconnect_time_us' => int 68734
 'connect_time_us' => int 45485
 'namelookup_time_us' => int 34369
 'pretransfer_time_us' => int 68833
 'redirect_time_us' => int 0
 'starttransfer_time_us' => int 68838
 'total_time_us' => int 60078775
 'request_header' => string 'PUT /v3/marketing/contacts HTTP/1.1
Host: api.sendgrid.com
Accept: */*
Content-Type: application/json