Teamviewer multi-user problem

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When i click on the blu ballon near the ID on Windows Server (2016 Strandard) I obtain this message.

The multi-user option is activated in the advanced configuration of Teamviewer 15.

User can access at their account on the Server when they are locally connected (inside the office).

I need to obtain different ID for every account like TW manual says, but I obtain only this error (Teamviewer is running in a phisical session consolle...).

Thanks