Heroku: Privacy error "Your connection is not private" is displayed

Updated Answer in 2020

Heroku now has Automated Certificate Management for all tiers above the free tier that allows for a ridiculously easy setup to have https working for your website.

To set this up:

1. In Heroku upgrade the tier to hobbyist or above (starting at $7/month)
2. In the CLI run the command heroku certs:auto:enable -a yourappname
3. In the CLI run command heroku domains. You should get a list of your custom domains and a list of the their DNS targets. After running the commands above the DNS targets you get should end in .herokudns.com instead of .herokuapp.com.
4. Now in your DNS (GoDaddy, or whatever DNS you are using) update the DNS to make sure that its pointed to the new .herokudns.com app instead of the generic .herokuapp.com

You might of course have to wait some time after finishing those steps for the DNS change to take effect. But now you have everything set up alright! Ta Da, you have DNS working for you!

For more info on any of those steps check heroku's article here

You get "Your connection is not private" error while loading your Heroku application through a new domain name because the existing SSL certificate is not valid for it.

As you can see from the error message:

This server could not prove that it is www.my_app.com; its security certificate is from *.herokuapp.com.

It is only valid for *.herokuapp.com domain name, in this case, it can be your-app-name.herokuapp.com. When you create a new CNAME and use that domain name instead of your-app-name.herokuapp.com, the exisiting SSL certificate can't validate it and displays this error to you.

To bypass this SSL error temporarily, you can enter chrome://flags into Google Chrome address bar to access advanced settings, locate "Allow invalid certificates for resources loaded from localhost" and enable this. By doing so, you can turn off this waring temporarily on your browser (only).

The solution to resolve this issue permanently is to get a new SSL for your domain. You can use the SSL Endpoint add-on from Heroku to use a private SSL with your domain name. This add-on charges you $20 per month. For more details of this add-on, read it from here or here.

Another option is to use Heroku SSL, a free feature that Heroku is currently offering. It seems they want to replace SSL Endpoint by this one. To find out how to install SSL for your domain name with Heroku SSL, read this article from NameCheap.com.

Source: Fix Your Connection Is Not Private Error In Your Browser

The issue is that you're most likely using force_ssl = true in your configuration, however you don't have a valid and authorized SSL certificate installed on your server.

To fix the error you have two possibilities:

• Disable SSL via force_ssl = false (not recommended)
• Purchase an SSL certificate issued from a certifying authority and install it on your server (such as nginx or Apache)