The attachment is not displayed for the following reasons:
1. Not filed: if the project is not filed, the filing information of the project can't be found on the filing website, resulting in the addition of the registration certificate can't be displayed.
2. Incorrect query conditions: the project name, filing number, reporting unit and other information are incorrect. Input during query will also make it impossible to query its additional information.
3. System problems: The filing website sometimes fails to display the filing information normally due to system problems, thus affecting the normal display of plug-ins.