can anyone help to solve the problem?

here is the error i got form my gmail.

Technical details of permanent failure:
DNS Error: DNS server returned answer with no data

And I would like to confirm my setting..

I have followed the same procedure with my local IP according to the link below

http://www.iredmail.org/install_iredmail_on_rhel.html

And I add the domain (global.com)that I want in roundcube webmail.

I have doubt that I can send to my gmail with email address (info@global.com) that I have create.

But I have that (global.com) domain, I know that I will have to do A/MX record in DNS .

I was confused the real domain name and the one we created in the roundcube webmail.

Could you guide me to solve this problem?

thanks,
joe

Thanks ZhangHuangbin! It`s  work after making some correction of A and MX record.
But I did not set a TXT record. Is it necessary?
And when I try to send to my yahoo and hotmail, it becomes a junk mail.
It works find with gmail.

And could you guide me some security issue for my IREDMAIL server.

thanks,
joe

Thanks a lot ZhangHuangbin! I
Can you tell me detail of how to set a TXT record?

And when I send to yahoo and hotmail, it becomes a junk mail although it goes direct to inbox of gmail.

please guide me again..

thanks,
joe

Thanks ZhangHuangbin !
I am very new  for the iredmail and mail server environment.
I have to setup this iredmail sever for my company and I was worried about the disaster situations.
Could you guide me how to prepare for the recovery (backup and restore)?

thanks,
joe