You receive the error "Invalid URL" when you try to join a Lync Online conference

When you try to join a Microsoft Lync Online conference, you may receive the following message:Additionally, there may be a potential overlap of some meetings.

This issue occurs�if�two users of the same Microsoft Office 365 tenant share the same user name (alias). Because of how Lync generates meeting URLs, two users on the same Office 365 tenant who have the same user name will share the same meeting URLs. This causes the Lync Online conference to become corrupted or to be invalid.

To resolve this issue,�if you have two users who have the same user name, change the user name of one of the users who has the duplicate user name. For information about how to edit and change user accounts in Office 365, see the following Help topic:�