Letsencrypt failed authorization

Hello,

I have installed virtualmin on a new droplet ubuntu 14.04 in digitalocean. My virtualmin server's url looks like this: “srv1.amaynu.com”. I want to secure this url so I downloaded letsencrypt from github to my home/user directory, and I continued with the following steps:

1. In virtualmin, I created a virtual server with the top level domain: amaynu.com
2. In Webmin Configuration module: "Full path to Let's Encrypt client command": /home/kumosal/letsencrypt/letsencrypt-auto
3. Webmin > Webmin Configuration > SSL Encryption > let’s Encrypt the only option I changed here is: "Website root directory for validation file" : A different Apache virtual host : amaynu.com
4. After clicking the "Request Certificate" button, I get the following message:

   Failed authorization procedure. srv1.amaynu.com (http-01): urn:acme:error:connection :: The server could not connect to the client to verify the domain :: Could not connect to http://srv1.amaynu.com/.well-known/acme-challenge/lb84Bqb0gqiKDgTCXzOZqqw1Roi3j5tTDKwv4tnpmWI
    
   IMPORTANT NOTES:
    - The following errors were reported by the server:
    
      Domain: srv1.amaynu.com
      Type:   connection
      Detail: Could not connect to
      http://srv1.amaynu.com/.well-known/acme-challenge/lb84Bqb0gqiKDgTCXzOZqqw1Roi3j5tTDKwv4tnpmWI
    
      To fix these errors, please make sure that your domain name was
      entered correctly and the DNS A record(s) for that domain
      contain(s) the right IP address. Additionally, please check that
      your computer has a publicly routable IP address and that no
      firewalls are preventing the server from communicating with the
      client. If you're using the webroot plugin, you should also verify
      that you are serving files from the webroot path you provided.

Can anyone here explain why I get this error? thanks