el capitan

Simply saying "doesn't work" is not a helpful description to aid troubleshooting. What happens when you try recovery drive?

About macOS Recovery - http://support.apple.com/kb/HT4718 - "OS X Lion and later include OS X Recovery. This feature includes all of the tools you need to reinstall OS X, repair your disk, and even restore from a Time Machine backup." - Also information about Internet recovery.

If you need to install from scratch, what exact model computer do you have? Some early models will require a DVD.

Are you booted into the Recovery Partition (command - R on a restart)? Have you ever downloaded El Capitan using your Apple ID? If you go to the App Store Purchases tab, does El Capitan show there? See if the download link below works.

Are you trying to reinstall El Capitan or do an erase and reinstall?

You can try to download it at the link below. If it won't let you, then your only options are to upgrade to Sierra/High Sierra or find an older computer where you can download it using your Apple ID.

El Capitan