Invalid value passed for url

I'm making a curl post via php with the following code and am receiving the error "Invalid value passed for url"

$headerArray = array("Content-Type: application/json;charset=UTF-8",

"X-com-zoho-subscriptions-organizationid: 307921614",

"Authorization: Zoho-authtoken ".$authToken

);

$ch = curl_init();

curl_setopt($ch, CURLOPT_URL, $url);

curl_setopt($ch, CURLOPT_HEADER, true);

curl_setopt($ch, CURLOPT_POST, 1);

curl_setopt($ch, CURLOPT_POSTFIELDS, $data);

curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);

curl_setopt($ch, CURLOPT_HTTPHEADER,$headerArray);

curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, 0);

curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, 0);

$resp = curl_exec($ch);

RETURNS THE FOLLOWING

Server: ZGS

Date: Mon, 07 Nov 2016 21:35:51 GMT

Content-Type: application/json;charset=UTF-8

Transfer-Encoding: chunked

Connection: keep-alive

Set-Cookie: 56dd2ec83e=d6fe3e1ebaa718ad24acc1c4d11cd116; Path=/

X-XSS-Protection: 1

X-Content-Type-Options: nosniff

Set-Cookie: zsmcscook=e5da90cd-a544-42dd-8511-641108c42cc9; Path=/; Secure

Set-Cookie: JSESSIONID=1B0720DD6BAF5DD57FE7B77E89B3DFCE; Path=/; Secure; HttpOnly

Cache-Control: no-store, no-cache, must-revalidate, max-age=0, post-check=0, pre-check=0

Pragma: no-cache

BUILD_VERSION: Nov_04_2016_4955

CLIENT_BUILD_VERSION: Nov_04_2016_4955

SERVER_BUILD_VERSION: Nov_07_2016_2_8516/

Vary: Accept-Encoding

{"code":2,"message":"Invalid value passed for url"}