Zend certified PHP/Magento developer

Magento 2 Website getting down

We host our dev and production sites on the same server. However, the production Magento site is going down randomly but, the dev is up at the same time.
It is like the website is not loading. I have no clue why it is happening.

I got notifications from the uptime robot about the website is done.
One real quick solution is i have to do a echo and exit on pub/index.php after that i load the site and it loaded the echo-ed content then comment the code. After that it loads the website perfectly.

Can anyone please guide me? any clue?