Ads Suddenly stopped showing

Thank God. My ads are back. The issue was with some optimization plugins which blocked the ads. Also my hosting provider did some optimization from his end.
This suggestion from WPMUDEV expert helped me. He identified my problem and posted the below reply.

This 404 error comes up in the browser console:
https://pagead2.googlesyndication.com/pagead/js/adsbygoogle.js.pagespeed.jm.6utLtnL9Kk.js – Failed to load resource: the server responded with a status of 404 (Not Found)
Which is correct, since the link that should be referred to is this:
https://pagead2.googlesyndication.com/pagead/js/adsbygoogle.js
You’ll want to ensure that scripts from their site aren’t being optimized by PageSpeed, as that’s what’s changing that URL like this, thus breaking the display of your ads. It’s discussed further over here:
https://productforums.google.com/d/msg/adsense/b7MmxzgQ0-0/4Aw5uy_PvPMJ
You’ll want to implement the changes advised over there, that should get this sorted for you.

I am posting this solution as it might help someone facing issue with sudden vanishing of ads though the account does not violate any adsense policies. Check for optimization tools, which might have bloscked the ads.
Thank you.