Websites are not accessible after website settings are updated via Plesk: 502 Bad Gateway

Symptoms

• In Tools & Settings > Apache Web Server, Apache restart interval value is set to 0.
• After settings update via Plesk sites show periodically show 502 Bad Gateway error.

Cause

When the interval is set to 0, Apache web server restarts immediately to apply new domain settings. Apache restart causes websites unavailability.

Resolution

1. Log into Plesk.

2. Open Tools & Settings > Apache Web Server.

3. Set up a non-zero Apache restart interval, for example 600 (interval is set in seconds).