The issue is only at the website home page's PHP script has the download behaviour but the rest of the website pages' PHP script run normally. In this article will show two solutions. This issue is very hard to debug because there are no helpful logs that will give hint on solving this issue. Actually, I was debugging a "Permission denied" issue and the fixes I tried to apply to this resulted to our main topic issue. The web server setup: Nginx as reverse proxy to Apache and under a web hosting control panel.