sukh

Why is the owner creating the appointment that way, why don't they follow the process as appointment 2. There shouldn't really be a need to go in directly to make an appointment, it should be sent there.

Is yours related to a browser type or an attachement type? For those users it doesn;t work for, test against different browser/attachment/PC etc...

Or setup the PA as a delegate on the Head's OLK.

Not sure what Exch has to do with SMS, I would have thought that was mobile network provider

Only internally though right, as you haven't exposed the 2010 namespace externally or moved it and used a legacyURL.

If there's ISA in the play here then yes, that would depend how it's been setup internally.

It's not an issue, it's not supported and does not work with Exch 2003.

I assume you are testing within the LAN and not extertnal, if that is the case the it will use windows credentials, that's normal. It only uses basic from external. So I assume it logs you in straight away in OWA 2003?

It's in AD. Just to understand what you have done. 1. Accessed the 2010 OWA Namespace with a user whose mbx is on 2003 and you login automatically or get prompted for authentication, i.e login page?

Make sure the cert is in the root cert exists in the local store on the Exch server, it does not need the FQDN of the Exch server itself. I assume you are using split DNS otherwise you must have the FQDN or OLK clients will receive prompts.

Not sure if you are saying it's an issue or it doesn't natively work, fyi it's the latter :-)

It will query AD and see where y our mbx is located and proxy your connection to the appropiate Exch server

How to remove Exchange Server 2003 from your computer leave the admin group for 2003.

Ideally, if you can remember what has/had been done? For e.g When the server failed, was it simply removed from the network or was it recovered and then removed gracefully from adsiedit? Or was is simply removed from adsiedit? I would 1st off start by running the ExchBPA and see what that moans about and then look at the config partition and see if you see any instanaces of Exch 2003?

Dont see why it won't work with Active-Sync, is this what you're referring to?

How to Configure Exchange 2010 Certificate - Direct Experts Blog Managing Certificates in Exchange Server 2010 (Part 1)

In that case you have to follow this Upgrading Outlook Web App to Exchange 2010 - Exchange Team Blog - Site Home - TechNet Blogs

The NDR you have posted doesn't contain the full status code, the issue to me seems to be with your ISP and their sync process. They may be only syncing certain objects/objectclasses i.e User and not DL. Or something may have changed which does not sync all that is expected. As for moving the non-working DL SMTP to your account, which then seems to work, says what I suspect above.

From Exch side, there isn't any effect. I would clean up the dead Exch 2003 server if hasn't been done sone already.

Sorry, I still dont know what you're actually trying to do now, You've confused me.# Are you saying you want both 2003 & 2010 to be up and running, ie, outlook and owa, and if one platform fails, i.e 2003 or 2010, you want to move the user to the other so they can continue to work?>

Depends how long you want co-existence for an if OWA is exposed externally too.

It seemz as if the user maybe hitting refresh, have yiu seen the issue 1st hand youraelf? ForDifficulty is that yiu cany reproduce the issue right? The message is actually being several times and yiu can see this in the sent items, when AV is typically involved you dont see that. You say yiu have tried other browsers, which ones?

Seen my comments above?

not supportex yet unless you deploy 2013 in a new forest. http://technet.microsoft.com/en-us/library/aa996719(v=exchg.150).aspx

Can you test with online & cache mode?