Hi Husain
Can you confirm the following first?
i) Does your REST adapter have the polling feature as described in the following? Your system needs to be at least 7.31 SP16 or 7.4 SP 11.
PI REST Adapter - Polling a REST API
ii) Confirm my previous comment - is there any possibility to have more than 1 files that needs be downloaded?
Regards
Eng Swee