Recently we have come across issues whereby when we are changing a users AD attributes such as their proxy addresses and SIP address to match their new name. We are seeing that once changed they are unable to sign into Skype. Unfortunately we only get a generic error message saying that their sign in information was wrong. After looking through all the obvious internet suggestions such as clear the Cache try on different machines I finally found the issue.
When looking in AD as it turns out there is actually an attribute called ‘msRTCSIP-PrimaryUserAddress’, when changing a users name this will not change with it and will need changing manually. If there is no value specified you will need to enter the users new name in the following format:
Hope this helps!