What does 502 error mean and why does it occur?
Hosting service customers may encounter an HTTP 502 Bad Gateway error. It is of short duration, no more than a few seconds. May occur at the beginning of each following hour. The error is related to the technological need to restart the HTTP server software only in case of making changes to the WWW-domain settings by any of the hosting users using the ISPmanager control panel. Performed by all hosting providers regularly it is not possible to reboot less often, because the pause between making changes to the settings and their entry into force will be too long. This error does not negatively affect the availability of sites. You can verify this by connecting monitoring tool like Google Analytics.