Why is Splunk not reading SOAP XML for CURL script with error "Premature end of file"

We use custom CURL scripts to update data on our dashboards. We have to add another custom script, but this one will need to use SOAP requests. We've created the scripts an the XML file with the SOAP request and when we run the script manually from the command line on the Splunk server, we get back the expected 200 status. The issue that we run into is that we get a status 400 when we run the same script from the Splunk app (Data Input). We get the error below about the MXL file. Request parsing failed. Could not parse XML; nested exception is org.xml.sax.SAXParseException; lineNumber: 1; columnNumber: 1; Premature end of file. Anyone have any suggestions on why it works one way and not the other? Thanks