How to send money using blockchain API?
You don't have to use all the optional variables in your request link, specially when you have not set a second password, etc...

this suffice the request to send your transaction:

$json_url = "https://blockchain.info/merchant/$guid/payment?password=$firstpassword&amp;to=$addressa&amp;amount=$amounta&amp;fee=$fee";


even if you remove "fee" variable, it would still work but you should consider 0.0001 miners fee that is there by default for minimum miners fee.

also you can get these values from the response:

$json_feed = json_decode($json_data); 

$message = $json_feed-&gt;message; 
$txid = $json_feed-&gt;tx_hash; 
$notice = $json_feed-&gt;error;