Thank you for your assistance. I have attempted to install the WordPress PDF Viewer add-on by navigating to Dashboard > Downloads > Settings > Updates and installing the wpdm-pdf-viewer.zip file. However, despite these efforts, the add-on continues to appear as uninstalled.
Prior to the recent update, the WordPress PDF Viewer was installed and functioning correctly. We are unable to identify the cause of this issue.
Could you please provide guidance on how to resolve this matter?