Error 521 using cloudflare on two droplets same one pointing as subdomain.

Noob,

After installing the one click install I’ve faced a couple different issues. Any advice is appreciated:

Background: Two Droplets, Droplet A is primary domain (i.e. example.com) and Droplet B is subdomain (sample.example.com). For droplet A i have used cloudflare and updated appropriate DNS records. All is working fine on Droplet A and associated urls. For Droplet B, I am getting an Error 521 when trying to connect through the url name (i.e. sample.example.com --> Error 521), when I try via the IP address I get a failed page load.

Question to make sure I’m doing it right:

1. When establishing the DNS records for the subdomain (ie. sample.example.com), should I just add the A, AAAA and NS records to the existing primary domain DNS records (i.e. example.com)?

2. Do I need to run the Apache virtual host tutorial? (It seems that the one click wordpress install already does that)

3. For cloudflare integration, I added all of the subdomain records I could (A, AAAA)

4. I have used A and AAAA records in lieu of a CNAME, so A record for .example.com and A record for www.example.com, and likewise for AAAA records of which each is independently pointing to its respective IP (from the relevant droplet).

Please note that I am not a programmer whatsoever but I want to learn because I’m tired of not understanding whats happening, i know its a slow process and I’m appreciative of any advice and directions.

Cheers.