While .vsd, .vdx and .vss import is not supported in Confluence Server, there are a number of ways you can convert these to a .drawio diagram and add them to your instance.

Convert to a .vsdx diagram: Open the diagram file in your normal Microsoft editor, version 2013 or later, and save it as a .vsdx file. Create a new draw.io diagram in your Confluence Server instance, then drag and drop the .vsdx file into the diagram editor.

Use draw.io: Create a new diagram in our online editor, then drag and drop the .vsd, .vdx or .vss file onto the drawing canvas. Copy and paste the diagram into a new draw.io diagram in your Confluence Server instance.