Starting with the release of Strategy ONE (March 2024), dossiers are also known as dashboards.
It is expected to see your user being populated automatically when Sharing a Dossier in Library.
When experiencing this issue, the active user will not be populated, and searching for existing users will return no results.

Option 1. Rebuild the configuration index
Through Developer, navigate using the following options:

Option 2. Turn the scheduler off and on.
Through Developer, navigate using the following options:


After that, repeat steps 1 through 5 making sure to check the 'Use Strategy Scheduler'.
Then, retest the issue in Library.
If the issue persists after this, please contact Strategy Technical Support and reference this Knowledge Base Article.