Quote from: mdiu12 on May 10, 2017, 11:52:27 AM
My joomla version is Joomla! 3.5.1 Stable and VirtueMart 3.0.10.
Those versions are very old and seriously insecure and should not be used on a live site.
https://www.joomla.org/announcements/release-news/5693-joomla-3-6-5-released.html
http://forum.virtuemart.net/index.php?topic=118683.0
You should check if your site has been already hacked.
Not sending out order emails may be because the payment plugin does not return a confirmed order status, incorrect settings for sending out the emails in VM configuration or an error in creating a pdf invoice, such as lack of memory on the server.