How to login user? -----winnet.dll

CookieData:array[0…100] of Char; CookieLen:DWORD;

CookieLen:=100;

InternetGetCookie(url?opendocument),PChar(‘DomAuthSessId’),CookieData,CookieLen);

DHTTP.Request.Connection := ‘Keep-Alive’; //Proxy-Connection: Keep-Alive

DHTTP.Request.ExtraHeaders.Add('Cookie: '+CookieData);

DHTTP.Get(URL$file\filename,WordStream);

domino 5 success

but domino 6 failture

why?