Consider the following scenario:
- You create a Microsoft Office 365 account for a user in a domain environment.
- The user's Office 365 account user principle name (UPN) differs from the user’s domain account UPN. For example, the user’s domain account UPN is "John Doe@domain.com." However, the user’s Office 365 account UPN is "John.Doe@domain.com."
- The user tries to sign in to Lync 2013 from a domain-joined computer in the environment.
This issue occurs because Lync 2013 tries to obtain the UPN of the domain account instead of the UPN of the Office 365 account.