Validation Error : Missing proxy query parameter.

Hi, We have integrated esignlive application form submission using the following guide in php . https://www.esignlive.com/blog/esignlive-how-to-create-and-send-a-package-with-rest-in-php/ We have successfully created and sent packages from the sandbox account. After we changed to the production environment ie, with api url : https://apps.e-signlive.com/api it works fine with some of pdfs but for one pdf we are getting an error like in this page ( https://apps.e-signlive.com/servererror/400?messageKey=error.unauthorised.proxyMissing&packageId= ). What might be the reason for this error ( Validation Error : Missing proxy query parameter. )? Thanks in advance!