Hi!
When you open the page in the browser, the response from the server is ok.
And for search bots the answer is 500, and gives an error:
http://prntscr.com/iau0en
Joomla: 3.6.3
VirtueMart: 3.2.12
Thanks for your answer! :)
https://developer.joomla.org/security-centre.html (https://developer.joomla.org/security-centre.html)
You should consider updating Your Joomla
Jörgen @ Kreativ Fotografi