How can I run a cron job every 15 mins on Jenkins?

This is what I've tried :

On Jenkins I have a job set to run every 15 mins using this cron syntax :

14 * * * *

But the job executes every hour instead of 15 mins.

I'm receiving a warning about the format of the cron syntax :

Spread load evenly by using ‘H * * * *’ rather than ‘14 * * * *’

Could this be the reason why the cron job executes every hour instead of 15 mins ?