Internet User can't connect to Outlook (Exchange 2010)

[Sam_1]

Hi,

Using Exchange 2010

I've set all virtual directories to be mail.domain.com and I have setup AutoDiscover as a A record to point to mail.domain.com address.

Everything I can think to configure is pointing at mail.domain.com.

When internet user connect to Exchange using Autodiscover it find exchange server route and add account successfully but after restarting the outlook it prompt "can't start microsoft outlook. can't open the outlook window. The set of folder can't be opened.The File c:\user\appdata\m\o\ .ost is not outlook data file (.ost)

When trying to add email account manually it can't find the server (mail.domain.com) neither in exchange , pop3, imap

i can ping the mail.domain.server but still it's not working in outlook.

Am I missing something?

PLEASE HELP!!! THANKS