I am already 3 hours fighting with setting SSL certificate for a Heroku app. I am following [this tutorial](https://devcenter.heroku.com/articles/ssl-endpoint#customdomain-ssl), but when I run

```
heroku certs:add server.crt bundle.pem server.key --app my-app-name

```

I always get this error:

```
Resolving trust chain... failed
 !    No certificate given is a domain name certificate.

```

I have bought the SSL certificate at **DNSimple**. What's is still wrong, why am I missing. It makes me despair, even Google didn't help...

All help will be appreciated.