I am not receiving the download email from the Linklok test form

If you are not receiving the email from the Linklok test form or if you are seeing the error message Email send using mail function failed check the following
1) Check that the email is not in your spam folder. SomeServices like yahoo and hotmail have have strict spam filtering settings.
2) Make sure that the email address you have set in $SellerEmail is a real email address on the same domain where you installed Linklok. For example if you installed on www.yoursite.com you should use an email address such as sales@yoursite.com.
If you still have problems it could be that the PHP mail() function has been disabled by your hosting company. Linklok also supports sending emails via the standard PHPmailer library via SMTP. To enable this
1) Upload class.phpmailer.php, class.smtp.php and class.pop3.php files to the same place where you have Linklok installed. You can find these in the phpmailer zip file below 
2) Add these lines near your other settings in Linklok.
$UsePHPmailer=1;
$EmailUsername="username";
$EmailPassword="password";
$EmailServer="smtp server";
$EmailPort=25;
The settings should be the same as you would use in an email client and ideally for the email address you have set in $SellerEmail.
If you wish to use a gmail account you can try the following settings (set $SellerEmail to your gmail address)
$UsePHPmailer=1;
$EmailUsername="you@gmail.com";
$EmailPassword="password";
$EmailServer="smtp.gmail.com";
$EmailPort=465;
$EmailServerSecurity="ssl";
$EmailAuth=1;

or on some servers

$UsePHPmailer=1;
$EmailUsername="you@gmail.com";
$EmailPassword="password";
$EmailServer="smtp.gmail.com";
$EmailPort=587;
$EmailServerSecurity="tls";
$EmailAuth=1;

If you see an error after the first email test login to your gMail account in a browser and check for a security message. Click the message and approve your server so that gMail allows it to send emails using your account.