Web site cannot scroll down

I see the problem in Chrome 41.0.2272.101 on a Mac.

Try deactivating all plugins. If that resolves the issue, reactivate each one individually until you find the cause.

If that does not resolve the issue, try switching to the Twenty Fifteen theme to rule-out a theme-specific issue.

It’s very strange. I have tried deactivating all plugins and changed the theme. Nothing works.

I switched to elegant theme I purchased earlier. It solved for a few hours. And now the problem re-appear again. Very strange.

Will it be a wordpress related problem?

Hm, I highly doubt it.

You weren’t able to scroll with 0 plugins active and the Twenty Fifteen theme enabled?

If so, try downloading WordPress again and delete then replace your copies of everything except the wp-config.php file and the /wp-content/ directory with fresh copies from the download. This will effectively replace all of your core files without damaging your content and settings. Some uploaders tend to be unreliable when overwriting files, so don’t forget to delete the original files before replacing them.