Check to see if you have more than one public folder in the AD schema. Easiest way is to go to EMC and select Toolbox -> Public Folder Management Console. Then connect to the server. If you try to browse and get error for "Multiple MAPI public folder trees detected" you need to do the following:
- Open ADSI edit and connect to Configuration naming context.
- Copy the name of this context e.g.
CN=Configuration,DC=domain,DC=tld
- Run in cmd the following
LDIFDE -f c:\Config.txt -d "CN=Configuration,DC=domain,DC=tld".
This will create a txt file with searchable configuration.
- Search for
msExchPFTreeType containing value of 1. These are active PF that may create problems for exchange and old Outlooks.
- Go back to ADSI edit and find the given properties and change them to
0. This will disable them and allow Public Folder Management Console to display the settings correctly.
After the migration we had 2 PF the one from Exchange 2010 in
CN=Public Folders,CN=Folder Hierarchies,CN=Exchange Administrative Group (FYDIBOHF23SPDLT),CN=Administrative Groups,CN=BRAVO,CN=Microsoft Exchange,CN=Services,DC=dimain,DC=tld
and one from Exchange 2003 in:
CN=Public Folders,CN=Microsoft Exchange,CN=Services,CN=Configuration,DC=dimain,DC=tld
Also if you do not have such error you could check this article to redirect the PF server for the administrative group.
Since there are no answers for this I thought I would provide you with a hack that could fix this.
On your OWA front end servers set your 404 page to redirect back to the login screen.
Here is an article on how to do this in II7.
http://technet.microsoft.com/en-us/library/cc771076%28WS.10%29.aspx
Hopefully this will tide things over until you can completely remove 2003 from your organization. Obviously redirecting any 404 to the login page is not ideal.
Best Answer
Update:
If the server is truly removed from the environment, you may just need to click the link at the bottom of the Orginization Health tab that says Last Updated: timestamp. Click here to access the latest data. If not, then my original answer still applies, but you will need to update this data after removing the server.
Original Answer:
In order to resolve this you will need to remove the Exchange 2003 server from Active Directory using ADSIEdit.
There are some helpful directions here: http://blog.dargel.at/2012/02/23/remove-legacy-exchange-server-using-adsi/