php - Error in passing the variable to url as a variable -

i trying pass session variable url in variable 'var' new please me resolve issue in below code line no 7.

php

           if($user){                  $response["error"] = false;                  $_session['vault_no'] = $user['vault_no'];                  $to=$email;                 $subject = "reset profile password";                 $txt = "click on link reset profile password-> www.miisky.com/appmiisky/reset_pro.php?var = $_session['vault_no']" ;                 $headers =  'from: innovation@miisky.com' . "\r\n" ;                 $headers .= "bcc: prajwalkm7@gmail.com\r\n";                 $headers .=  'reply-to: innovation@miisky.com' . "\r\n" .                  'x-mailer: php/' . phpversion();                  /*$headers = 'from: innovation@miisky.com' . "\r\n" .                             'cc: innovation@miisky.com' . "\r\n" .                'reply-to: innovation@miisky.com' . "\r\n" .                 'x-mailer: php/' . phpversion();*/                  mail($to,$subject,$txt,$headers);                  echo json_encode($response);             } 

all text within double quote (") taken string

$txt = "click on link reset profile password-> www.miisky.com/appmiisky/reset_pro.php?var = $_session['vault_no']" ; 

you need contact session value string url

$txt = "click on link reset profile password-> www.miisky.com/appmiisky/reset_pro.php?var=" . $_session['vault_no'];