This is most likely because the linked document has a "+" in its filename, which the PDF viewer or web browser cannot handle.
To resolve this issue:
- Launch the AV Capture desktop app.
- Remove any applicable related documents from the session.
- Remove associated Link Document hyperlinks from the agenda.
- Via Windows File Explorer - rename the files in their original locations.
- Re-import the renamed related documents.
- Recreate the Link Document hyperlink(s) in the agenda.
- Re-publish the session.