Apache stops working after a while?

I use it for my PHP website, which connects to an external MSSQL database. My problem is that when I haven't accessed my website for a while, it stops working. However, when I log in to the CWP control panel, it starts working again. This issue only occurs when the firewall is active.

Does anyone know how to solve this?
Thank you.

Does it actually stop working, or is your access to it prevented by the firewall? Have you whitelisted your IP address in /etc/csf/csf.allow?

Hello, thank you for your quick response.
I have investigated further and it appears that it is the MSSQL connection that stops working. Once I log into the cwp panel, it works again. This does not happen if I disable the firewall.