Consider the following scenario:
Microsoft Office 365 users (user A and user B) both have Microsoft Lync 2013 installed on their computers.
User A is in an organization that is not federated with user B's organization.
Neither user can enable an open federation.
User A creates a Lync Online meeting.
User B receives the meeting request from user A, and then user B clicks the Join Lync Meeting hyperlink in Outlook.
In this scenario, user B is not able to join the meeting. Additionally, user B receives the following error message:
An error occurred…
To resolve this issue, install the following updates: