Exchange 2010, one server, multiple email domains, no calendar access...

Hello Xperts

We have 1 Exchange 2010 Server in our organization.
On this server we have multiple domains.

one is our main public email domain: ""
one is our internal email domain: "INTERNAL"
there is one more domain by the name: ""

all usersaccounts are on the same AD Organization, but have different email adress domains.

Problem: Users from one naildomain are not able to see calendars of users from other mail domains even thought they are shared.

In Outlook we get a error like this (see attachment screenshot).

Can someone point me towards the source of this error?

Thank You
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it-swiss-eeAuthor Commented:
Hello Geeks

I got the solution myself:

Problem came due to a mix of two things.

1. we have some users where we prevent internet access with a bad proxy configuration in IE. Outloo calendar does not like this. This is because the autodiscoveryservice will not work cause it cant access the autodiscovery website.

2. Exchange does not like "INTERNAL" as domain, you should use a correct full domain name internal.local, so your dns settings and certificates correspond to the domain.

i changed both of these configurations. replaced bad proxy with a configuration of web control in kaspersky antivirus and I made internal email access in Exchange with transport rules.
(after changing the configuration I had to delete and recreate outlook profiles on user computers to make all work)

like this, everything works just fine.

Anyhows, thanks for Your help as this has pointed to the right direction...
Do your users resolve different hostnames for the Exchange Server?
Also, try adding internal MX records pointing to the exchange server for the email domains.

Hope that helps,
it-swiss-eeAuthor Commented:
thanks for your answer

they all use the same internal servername, (outlook configures automaticly)
it is something similar to servername.ourdomain.local
so what you are saying is to create an MX record "internal" that points to our mailserver?
Making Bulk Changes to Active Directory

Watch this video to see how easy it is to make mass changes to Active Directory from an external text file without using complicated scripts.

Yes, create the mx records for each domain on your internal company dns server
Please avoid the above instructions, MX record is for mail flow and not for Free/Busy viewing.

What I'd like to know is

==> Are users on same server able to view each others calendar?
==> Are users able to check if autodiscover is resolving correctly?
==> Do you have a cert installed on the Exchange box configured for OOO, OAB, UM, Autodiscover?

it-swiss-eeAuthor Commented:
Hello Exchange Geek

Thanks for Your good answer.
here is the answers to Your questions:

1. yes, they can see calendar, as long as they use the same emaildomain
2. autodiscover is resolving correctly for all users and emaildomains
3. we have a cert installed for all services, yes.

thanks for Your help
it-swiss-eeAuthor Commented:
first answers helped to point me into right direction. The solution I came up with after that makes everything just work fine.
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