Error received calling Ws with HTTAPI

I all
i'm try to consume a Web services with Scott Klement HTTAPI, the Web service
return "HTTP/1.1 500 Internal Server Error" . Below see httpapi_debug.txt
and http_result.txt content

which could be the problem ?

Thanks in advance

httpapi_debug.txt content

SetError() #25: SSL environment was already initialized!

http_url_post_stmf(): entered

getting post file size...

opening file to be sent...

opening file to be received

http_persist_open(): entered

http_long_ParseURL(): entered

DNS resolver retrans: 2

DNS resolver retry : 2

DNS resolver options: x'00000136'

DNS default domain: MyComp.Com

DNS server found: 192.168.10.xxx

DNS server found: 192.168.10.zzz

-------------------
Dump of server-side certificate information:

---------------------
Cert Validation Code = 0

-----BEGIN CERTIFICATE-----
-----END CERTIFICATE-----
Serial Number: zzz
Common Name: zzzz
Country: ZZ
State/Province
Locality:
Org Unit: Firm
Protocol Used: TLS Ve
http_persist_post():
http_long_ParseURL():
do_post(): entered
POST /ZZZZZZZ
Host: host
User-Agent: http-api/
Expect: 100-continue
Content-Length: 1280
recvresp(): entered
HTTP/1.1 100 Continue

SetError() #13: HTTP/1.1 100 Continue
sendraw(): entered
<soapenv:Envelope xmlns:soapenv="http:..............
..............

recvresp(): entered
HTTP/1.1 500 Internal Server Error
Date: Sat, 01 Feb 2016 13:56:46 GMT
Server: Gateway
Connection: close
X-CorrelationID: xxxx
Host: ffff
User-Agent: http-api/1.23
Content-Type: text/xml;
charset="utf-8"

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

recvdoc parms: identity 0

header_load_cookies() entered

recvdoc(): entered

SetError() #0:

<env:Envelope xmlns:env="http://schemas.xmlsoap.org/soap/envelope/";>

<env:Header></env:Header>

<env:Body>

<env:Fault>

<faultcode>env:Server</faultcode>

<faultstring>[invalid field] [invalid field]</faultstring>

<detail fault:type="faultDetails"
xmlns:fault="http://www.vordel.com/soapfaults";></detail>
</env:Fault>

</env:Body>

</env:Envelope>
SetError() #44: CommSSL_read: connection broken
SetError() #13: HTTP/1.1 500 Internal Server Error
http_close(): entered

http_result.txt content

<env:Envelope xmlns:env="http://schemas.xmlsoap.org/soap/envelope/";>

<env:Header></env:Header>
<env:Body>
<env:Fault>
<faultcode>env:Server</faultcode>
<faultstring>[invalid field] [invalid field]</faultstring>

<detail fault:type="faultDetails"
xmlns:fault="http://www.vordel.com/soapfaults";></detail>
</env:Fault>
</env:Body>
</env:Envelope>