If you are facing issue like order confirmation email is not going to sent to customer after success order, just make a small change in order.php file.

app/code/core/Mage/Sales/Model/Order.php

First, create one directory structure on the path below, then copy and paste the file to the path below.

app/code/local/Mage/Sales/Model/Order.php

Now, change from

$mailer->setQueue($emailQueue)->send();

to

$mailer->send();

That's it. I hope this will help some.

Thanks.