Echosign

I am trying to do echosign integration (to do signature on pdf) by using the api call and we are using the api as https://secure.echosign.com/services/EchoSignDocumentService17?wsdl and operation as sendDocument.   I have passed pdf document to fileInfo using url parameter but I am getting below fault  <soap:Fault xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/"><faultcode>soap:Server</faultcode><faultstring>Adobe Sign was unable to process your PDF document(s) because we were unable to read one or more of them. This can occur if your document is corrupt or badly formed. You may wish to use the free Adobe Acrobat Reader to re-save this document to repair it. (apiActionId=CBJCHBCAABAA4BIP8rKsJ-dp-7zfiEWja3TzbW4bjK4v)</faultstring></soap:Fault>  Can any one please help me to resolve this issue. Thanks in advance!