I personally had horrible experience with my ISP’s DNS,
I don’t even want to talk about it. It failed majority of the time.
If your browser says ‘DNS Error’ and webpages will not load,
If you need to Refresh (F5) many times before the webpage loads,
If you cannot see images in the website and the page looks weird,
If your Appstore cannot download apps through Wi-Fi,
If your Google Playstore fails do download an app through Wi-Fi,
this is the fix for you.
There are two ways of doing this,
Do Fix1 if you have no clue how to navigate settings of your router.
Do Fix2 if you clearly know what you are doing with your router settings.