The user's Skype for Business Online service plan isn't valid
Important
Skype for Business Online operated by 21Vianet in China will be retired on October 1, 2023. If you haven't upgraded your Skype for Business Online users yet, they will be automatically scheduled for an assisted upgrade. If you want to upgrade your organization to Teams yourself, we strongly recommend that you begin planning your upgrade path today. Remember that a successful upgrade aligns technical and user readiness, so be sure to leverage our upgrade guidance as you navigate your journey to Teams.
Skype for Business Online, excluding the service operated by 21Vianet in China, was retired on July 31, 2021.
Sorry, the Skype for Business Online service plan assigned to this user is not recognized, or is invalid.
Go to the Microsoft 365 admin center* > Active users and assign a valid service plan to this user.