Original sub-domain of rails app to Heroku

Question

I would like to set up original domain to Heroku. But I got stuck. Could you help me?

What I did is as follows;

①heroku domains:add www.example.com

②DNS setting

a www 75.101.163.44
a www 75.101.145.87
a www 174.129.212.2

③host www.example.com

and then I got this.

Host www.example.com not found: 3(NXDOMAIN)

Answer 1

Heroku suggests not to use naked domains because they're fragile.

You need to set up a CNAME domain to Heroku like this:

CNAME www your-app-name.herokuapp.com.

Remove the A records. Please see the rest of the docs here: https://devcenter.heroku.com/articles/custom-domains