YouTube has changed their Partner Program polices recently. Now if you want to monetize your YouTube channel, you need to have at least 1,000 subscribers and 4,000 hours of watchtime during the past 12 months. YouTube wants those creators who positively contribute to the community. They will roll out the new policy to existing channels on February 20th 2018. So if your YouTube channel doesn’t fulfill the requirement, you have time till to 20th February.