Firstly, check your passwords, your API code and your wallet ID. If the problem still persists, then make sure that the blockchain wallet services are running on your server on port 3000.
You can check the working of blockchain wallet services by hitting the url in browser i.e. http://localhost:3000. if its giving response error "Not found" that means your blockchain wallet services are running. To send bitcoins to many users at a time, you can use the following API:
http://localhost:3000/merchant/$guid/sendmany?password=$main_password&second_password=$second_password&recipients=$recipients&fee=$fee
or use the following:
$address = null;
try {
// Uncomment to send
// var_dump($Blockchain->Wallet->send($address, "0.001"));
} catch (\Blockchain\Exception\ApiError $e) {
echo $e->getMessage() . '<br />';
}
// Multi-recipient format
$recipients = array();
$recipients[$address] = "0.001";
try {
// Uncomment to send
// var_dump($Blockchain->Wallet->sendMany($recipients));
} catch (Blockchain_ApiError $e) {
echo $e->getMessage() . '<br />';
}