Error reloading bind on server

I have to start from the very beginning. So please don't mind me if my post is so long.

My partner took dedicated server from The Planet data centre and he configured everythings for the server. But the hostname was with his company name "commsnet02" so that I changed it to gravity.thitsar.com and the the problems started.

The host name that I change didn't work properly. And I played much with nameservers, in both WHM & ssh. So he needed to fix DNS settings & nameservers again. I dont know what he did. Now he is unavailable for some reasons and I got some errors.

Our server has 5 IPs.

67.19.217.18
67.19.217.19
67.19.217.20
67.19.217.21
67.19.217.22

Main IP is .18.. but I think he modified it in ssh since the Main Shared Virtual Host IP in Edit Setup in WHM is showing the IP ending with .20. And now.. though gravity.thitsar.com is running properly, I got this error message whenever I enter into WHM.

Hostname A Entry Missing!

The server was unable to lookup an an A entry for its hostname
(gravity.thitsar.com). This is generally because the entry was never
added. However this could also be the result of your nameserver(s)
being down. If you would like to attempt to automaticlly add the
entry, Click here (it is a button).

When I click it, it shows :

Found your hostname to be: gravity.thitsar.com
Found your short hostname to be: gravity
Found your domain name to be: thitsar.com
Found your main ip to be: 67.19.217.18
If this looks correct,

Add A Entry (a button)

and then :

Zone thitsar.com does not exist, a new zone for gravity.thitsar.com
will be created.
Bind reloading on gravity using rndc Error reloading bind on gravity:
rndc: connect failed: connection refused
Created DNS entry for gravity.thitsar.com
Add Complete

I got the following error message whenever I create new accounts too.

Bind reloading on gravity using rndc Error reloading bind on gravity:
rndc: connect failed: connection refused
Created DNS entry for gravity.thitsar.com

And he told me to create accounts on the .18 IP, but today when I try
to create one account, it show only 22, 20, 21 & 19 but I can see .18
IP in Show IP Addresses.

And there is another problem. Last 5 days ago, all mails sent to my domains' emails are lost in somewhere. No mail delivery return error messages. They just like losing somewhere. I don't know what's wrong with that.

Now I am on tight budget so that I couldn't hire any linux admin to do it and I am just a newbie in Linux...

Somebody please help me out ...

Regards,
Samuel

 

And there is one problem left too..

When I create new accounts, it suppose to inform that to admin contact email but it doesn't anymore, starting from last 3 or 4 days.

and when I changed hostname in WHM last few weeks & got error and played with .conf files & nameservers in ssh, gravity.thitsar.com doesn't usually resolve to main IP, .18.... but now it seems like it is resolving to .18 IP..

 

btw, I see that bind is up in Service Status in WHM