HTTP Upload. -5120 Error

Hi, All.

I have writed a code which perform http upload with Symbain http api. It's working good on 5 from 6 cellphone operators.
On one operator at beginning of upload process I get from uploader -5120 error = No response from DNS server and GetNextDataPart function was never caused by api.

But using another part of my program i get connected RSocket via sockets engine to server with same host name on same operator.

Why http api returning -5120 error, when simple socket working perfecctly?


Header example of my request:

POST /Upload.ashx?parameter1=010&parameter=2&param=3 HTTP/1.1
Cache-Control: no-cache
Connection: Keep-Alive
Host: www.myhost.com
Accept: */*
Content-Length: 61585
Content-Type: multipart/form-data; boundary=-------------158046840414746426

---------------158046840414746426
Content-Disposition: form-data; name="file" ;filename="test.3gp"
Content-Type: video/3gpp