I ran into this problem when using Apache as a forward proxy. It fixes the issue when trying to parse the XML but not all of the HTTP headers have been stripped, and you end up with this error:
wsdl: XML error parsing WSDL from https://soap.acme.org?WSDL on line 1: Not well-formed (invalid token)
Adding two "skippable" headers with title casing.
I ran into this problem when using Apache as a forward proxy. It fixes the issue when trying to parse the XML but not all of the HTTP headers have been stripped, and you end up with this error: