Recently I’ve been working with a customer who is going through a rebrand, as part of this change they were updating their SIP and Email addresses with the new brand name, keeping the same format before the @ sign.

Since this is a large change we started the preparation some time before the actual legal cutover was due, the changes to Exchange and Skype were nothing out of the ordinary and allowed the customer to receive emails on the new domain and allowed test users SIP addresses to be changed.

All was well with the infrastructure changes until we came to test client connectivity. The Skype client required the sign in address to be changed but once done they signed in successfully, it wasn’t until we came to Outlook we discovered an issue.

When testing the creation of a Skype meeting request we encountered an error: “The user accounts in Outlook and Lync do not match. Please make sure you are signed into both applications with the same user name and privileges”

We knew the SIP address was correct and that the SMTP address had been changed to match. We tried repairing the Outlook profile which did not make a difference.

Out of interest we had a look at the Global Address List and it still showed the account with the original SIP address, which was strange so we decided to ensure all the address books were updated by running the following on the Exchange server:

Get-globaladdresslist | update-globaladdresslist

Get-offlineAddressbook | update-offlineaddressbook

Get-Addresslist | update-addresslist

Once the client then downloaded the address book it was able to create meetings using the new SIP domain information.

This problem was unique to the fact we were making the change and immediately testing so not allowing enough time for Exchange to automatically update itself if we were doing this during the cutover window we would not have run into this,

Hope it helps.