Key not recognized

[Shanti Websolution]

Code works perfectly.
While I create QR Code and try to scan with Google authentication app I am getting Key is not recognized error.
Kindly help

Here is my code

require 'vendor/autoload.php'; $username = 'jayesh_d'; $salt = $this->config->item('salt'); $ga = new PHPGangsta_GoogleAuthenticator(); $secret = $username.$salt; echo '<img src="'. $ga->getQRCodeGoogleUrl('', $secret).'" />';