I have taken following steps to find the problem:
- Viewed the HTML source code using firebug and found page not found error
- Checked the .htaccess file, but there were no problem
It was very surprising because none of my site contents on that directory – /usr/share/ and didn’t do anything which may take this type of effect.
Options FollowSymLinks MultiViews
To fix – Commented out the Alias line(1) and then restarted Apache. Everything started working fine for me.