Hi,
This indicates that there is a fatal error somewhere.
What we need is the fatal error message to be able to say anything.
You'll have to check the PHP error log of your server where the fatal error message should be logged.
It could be anything but I see that you have a recent version of PHP while you have an old version of Joomla and HikaShop. This might be the reason why it crashed but it could be something else anterily. The error message will allow you/us to know where the problem is coming from.