error:403 (Server response:403 forbidden )

Hi to all ,
I am  Using Codeignter RESTfull APIS ..
In Android When Ever I am upload images I am Getting error 403(server response). other wise API working good .
Same API using IOS When ever Image uploads Also Its working ..
How to solve  This android Problem ....? In file uploading both (IOS and Andriod peoples using chunks of data ).....