Hi @Atharva_Agrawal,
Have a look through the troubleshooting hints at GitHub - pkp/pln: PKP Preservation Network Plugin, particularly:
Search the plugin’s logs in the ‘scheduledTaskLogs’ folder within the OJS
files directory. Files named ‘PKPPLNDepositorTask-id-datestamp’ should
be found there.
These log files might provide more information.
Regards,
Alec Smecher
Public Knowledge Project Team