Hi Balaji,
Even without looking into details, the error saying "5 recipients processed," doesn't seem good. Because if the destination is set to default, the job wouldn't try to send it to recipients after scheduling.
Apart from that, what is the size of the PDF file, when you refresh it manually and download to PDF. Please check that and Binary Maximum Stream Size parameter in properties of WebIntelligenceProcessingServer. If the PDF file size if more than 50mb, you'll have to increase that parameter value.
Thanks,
Mahboob Mohammed