[Ftpapi] ActionNotSupported ContractFilter mismatch at the EndpointDispatcher

I hope someone can help diagnose this issue. I’m not sure if the problem is on our end or on the client end,

And if the latter, I’m not sure what questions to ask.

We have a process using http_url_post_stmf that is receiving this XML response:

<faultcode xmlns:a="http://schemas.microsoft.com/ws/2005/05/addressing/none">a:ActionNotSupported</faultcode>

<faultstring xml:lang="en-US">The message with Action '' cannot be processed at the receiver, due to a ContractFilter mismatch at the EndpointDispatcher. This may be because of either a contract mismatch (mismatched Actions between sender and receiver) or a binding/security mismatch between the sender and the receiver. Check that sender and receiver have the same contract and the same binding (including security requirements, e.g. Message, Transport, None).</faultstring>

I did a http_debug, which gave the following at the bottom:

recvresp(): entered

HTTP/1.1 500 Internal Server Error

Cache-Control: private

Content-Length: 698

Content-Type: text/xml; charset=utf-8

Server: Microsoft-IIS/8.5
Server: Microsoft-IIS/8.5

X-AspNet-Version: 4.0.30319

X-Powered-By: ASP.NET

Date: Thu, 22 Jun 2017 15:32:52 GMT

SetError() #13: HTTP/1.1 500 Internal Server Error

recvdoc parms: identity 698

header_load_cookies() entered

recvdoc(): entered

SetError() #0:

<s:Envelope xmlns:s="http://schemas.xmlsoap.org/soap/envelope/"><s:Body><s:Fault t><faultcode xmlns:a="http://schemas.microsoft.com/ws/2005/05/addressing/none">a a:ActionNotSupported</faultcode>
<faultstring xml:lang="en-US">The message with Action '' cannot be processed at the receiver, due to a ContractFilter mismatch
at the EndpointDispatcher. This may be because of either a contract mismatch (mismatched Actions between sender and receiver)
or a binding/security mismatch between the sender and the receiver. Check that sender and receiver have the ame contract and
the same binding (including security requirements, e.g. Message, Transport, None).</faultstring></s:Fault></s:Body></s:Envelope>

SetError() #13: HTTP/1.1 500 Internal Server Error

http_close(): entered

Thanks for your help,
Charlie.