Adsense Ads (Appearing sometime ,sometimes not)

I have a website with 2000+ articles but articles are shortner in length.Around 200-300 words approx.
Till a week back all ads were displayed properly,Now when i open site i sometimes see ads on some articles.Sometime only one ad in some articles and sometimes no ads.
What the hell is going on,is it only me or happening to all.
Daily traffic is 15k +.All organic.

What should i do I have 4 ads on each post.

cache? maybe they dissapear on ur ip only

maybe there aren't many advertisers in your niche.

I've got the same issue but found it was cache related. I then used firefox and saw ads are running fine