- Make sure that the user has a valid Skype for Business Online license in the Office 365 portal and that the sign-in status of the user is set to Allowed.
- After you've assigned an appropriate Skype for Business Online license, wait approximately 30 minutes, and then determine whether the user can sign in to Skype for Business Online through any Lync 2013 or Skype for Business client.
- Whereas the service typically takes less than 30 minutes to provision a user, it can sometimes take up to 24 hours to fully provision a user for all services in Office 365. Therefore, wait 24 hours before you escalate the issue.
- Are you synchronizing from an on-premises Active Directory organization, and was the user's msRTCSIP-PrimaryUserAddress attribute already populated through a Session Initiation Protocol (SIP) domain that hasn't been verified by Office 365? In this situation, the user won't be provisioned in Skype for Business Online. If the issue persists, submit a support service request.
- The user doesn't have a Skype for Business Online license.
- Not enough time passed to allow for replication from Microsoft Azure Active Directory to Skype for Business Online.
- There's a conflict with the user’s SIP address.
- The user is in a location that restricts instant messaging usage. Therefore, the user isn't provisioned for Skype for Business Online.
- There are provisioning issues in the on-premises Active Directory.