Zend certified PHP/Magento developer

Magento 1: store view not loading (error 502/504)

we have a Magento1 installation. We have 6 store views, each one with a different domain. Of these 6 store views, 5 work perfectly (so, if I go inside store2.com everything loads correctly – same for store3.com – store4.com – etc…). Also Magento’s backend works fine.

One store view, however, since this morning gives us a 502/504 error (bad gateway). So, everytime I go inside store1.com, I get a 502 or a 504 error (which, people at cloudflare say it’s related to the server response time).

What might be the cause of this?

I tried to reset the server (I’m no Magento expert, mind you), check the logs and see the running processes. Everything seems in order.

No changes has been made between this morning, before it begun to give this issue, and after.

Thank you for any advice you can give me