I have a new question.........
Now my rounducbe is work fine , sending and receiving are good!
But ,when I sent a mail ,the user mail address is "abc@mail.xyz.ok.com",which "mail.xyz.ok.com" is my mail server in DNS setting.
I wish to have a mail address with "abc@xyz.ok.com" just like my openwebmail and outlook setting.
I tried to change $rcmail_config['username_domain'] = ''; to $rcmail_config['username_domain'] = 'xyz.ok.com';
But after I make this change, the login failed.
How to fix this problem, thanks.