Starting with the release of Strategy ONE (March 2024), dossiers are also known as dashboards.
SYMPTOM:
In Strategy 2021 Update 6, ‘Configure Transaction’ option is not available from web if click More
in the upper right corner of the visualization of the Grid (Modern) as shown below:

Refer to Product Help on how to create transaction grids for dossiers in Strategy 2021 Update 6:
Transactions in Grids
The user has privilege of “Web configure Transaction” as shown below:

CAUSE:
Transactions are only available in Library and Workstation.
If attempt to open a dossier in Strategy Web or any embedded instance of Strategy Web that was saved with a newer feature from a modern product, the following message appears.

Dossier cannot be opened
This dossier users a feature that is not compatible with Strategy Web. Use Strategy Library, Strategy Application, or Strategy Workstation to view or edit this doddier.
ACTION:
Configure Transactions in Library or Workstation.

Further readings:
Features Incompatible with MicroStrategy Web