Here is a list of possible solutions.
I added websites to CWP but they don't work. Why? It's turns out that the CentOS nameservers didn't work for me. I used CloudFlare.Com instead. CloudFlare operates a super high-performance DNS network that points your domain name to your IP address. I use the free plan. CloudFlare also operates a content delivery network (CDN) as well, but I am not currently using that yet.
Here is a short example of how I use CloudFlare and DNS records:
My domain name registrar, like Domains.Google, gets the browser request for my domain name. It forwards that request to CloudFlare via the CloudFlare nameservers that I had entered at Domains.Google. CloudFlare points the request to my actual domain via the DNS records I had previoudly set up at CloudFlare.
Domains.Google => CloudFlare.Com (via DNS records) => My Website.
How to set up your DNS records at CloudFlare.Com
The big picture for setting up DNS records:
1. Point domain name to IP address using "A" record.
2. Point "www" to IP address using "A" record .
3. Point "ftp" to domain name using "CNAME" record.
4. Point "webmail" to IP address using "A" record.
5. Point "mail" to domain name using "CNAME" record.
5. Point domain name to mail server using "MX" record.
6. Set up three "CNAME" records associated with mail: pop3, pop and imap.
6. Set up three "TXT" records associated with mail: DMARC, SPF and DKIM.
7. Set up a "CNAME" record associated with mail: smtp.
I just set up a email account without doing step #6. I sent emails to my regular GMail account, and where did they all go? GMail SPAM.
Here are some tools to help you: Leaf DNS, DNSChecker and MXToolbox.
Are you getting a RoundCube Internal Server Error? Check out this fix: Roundcube1.5.x Internal Server Error - FIX. Check forum.centos-webpanel.com for the latest articles on CWP.