Sharepoint 2010, cannot open/edit office files due to credential fail

I found some similar posts and tried their solutions, none of them fix my issues.

We are using Sharepoint 2010 with Office 2010 and IE9. Below on our settings. users have no problem logging in and view SharePoint page, but as soon as they click into Office files, they will prompt for login, and the login will fail even inputting a correct one. Opening  files on browser has no problem, but some of the office files are not able to edit on browser.

I have tried everything here with no luck : http://www.sharepointdiary.com/2012/04/sharepoint-keeps-asking-for-password.html

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AAM settings:

http://sharepoint.domain.com Zone: Default          

http://sharepoint                         Zone: Intranet

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IIS

Site bindings:

http sharepoint.domian.com 80  *

http  sharepooint  80  *          

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DNS, Forward lookup zones:

Name:                  Type:             Data:

Sharepoint           Alias            Sharepointserver.domain.com

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IE Settings:

Add site to Intranet Zone, security level low, and change User Authentication: “Automatic Logon with current user name and password”