Do you mean you want to disable Skype for Business Online user?
If so, this issue occurs because the appropriate license isn't applied to the user. Therefore, the action fails with a license validation error.
To resolve this issue, apply the correct license, and then try to disable the user again. For Skype for Business Online, an Exchange Plan 2 license or higher is required.
For more details, you could refer to this article.
If I misunderstand your words, please give us more details. Thanks for your understanding.
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