Here are some troubleshooting steps to try:

1. Check the document name: Verify that the file name or path you are using to open the document is correct.
2. Verify that changes are saved: Select File > Save and confirm that changes have been saved to the correct file.
3. Check the application status: Make sure the application is enabled and up to date.
4. Verify the permissions: Check that you have access rights to make changes to the document.
5. Check with your system administrator: Check that the permissions in your organization allow for editing of properties.