A site that was created in Parallels Plesk Sitebuilder 4.5 cannot be opened. The following error appears when you open it in a web browser
Gateway Time-out The gateway did not receive a timely response from the upstream server or application.
Other sites on the same publishing server are working fine.
The issue may be caused by big size of SQLite database file.
Delete old and unnecessary records from SQLite database per these KB articles: