i am trying to configure Exchange Server 2010 on Windows Server 2008 R2 to receive emails from the internet following the danscourses tutorials:

and i followed this video for the DNS & MX records:

http://www.youtube.com/watch?v=jdf_3DRssks

i don't have any windows administration skills, and i am stuck with the DNS configuration. and the following are my domain configuration i got from the hosting.

following are the steps i made:

1- Add new name server:

add > ns1.centors.com ip > Exchange Server Public IP: 41.233.26.131

2- Change the A record

change it to point to the public ip address > Exchange Server Public IP: 41.233.26.131

3- New cname record for www

and make it resolve to centors.com

4- New mx record for mail.centors.com

5- New A record for mail.centors.com:

name: mail ip: Exchange Server Public IP: 41.233.26.131

6- new A record for ns1:

ip: Exchange Server Public IP: 41.233.26.131

7- i made port forward in the router for SMTP and POP3 to the exchange server local ip address.

ISSUE: i have a user account in the active directory, and the user is member of the domain, the user is [email protected] and when trying to login with this account in outlook 2010 on other machine using following data:

• account type: POP3
• incoming mail server: mail.centors.com
• outgoing mail server: mail.centors.com

i always get the error: Authorization failed, check your server settings.

please advise what's wrong with the configuration, thanks in advance.