WinHttpSendRequest: 800C0057

I am trying to analyze crash using cdb.exe from windbg. I run an windows service to invoke cdb to analyze dmp that i passed in. Then send me the result.

Symbol search path is something like this:

d:\oldstyle;cache*d:\winsyms;srv*http://127.0.0.1:9094/home/apache/winsym

What i actually want is, download symbols from

http://127.0.0.1:9094/home/apache/winsym

and save to

d:\winsyms(local cache) 

Problem is something like this:

Unable to load image C:\Windows\System32\combase.dll, Win32 error 0n2 
DBGENG:  combase.dll - Partial symbol image load missing image info 
DBGHELP: Module is not fully loaded into memory. 
DBGHELP: Searching for symbols using debugger-provided data. 
DBGHELP: d:\oldstyle\combase.pdb - file not found 
DBGHELP: d:\oldstyle\dll\combase.pdb - file not found 
DBGHELP: d:\oldstyle\symbols\dll\combase.pdb - file not found 
SYMSRV:  BYINDEX: 0x1F 
         d:\winsyms 
         combase.pdb 
         6D54516506E95F4ABC3FBDAF3373F96D1 
SYMSRV:  UNC: d:\winsyms\combase.pdb\6D54516506E95F4ABC3FBDAF3373F96D1\combase.pdb - path not found 
SYMSRV:  UNC: d:\winsyms\combase.pdb\6D54516506E95F4ABC3FBDAF3373F96D1\combase.pd_ - path not found 
SYMSRV:  UNC: d:\winsyms\combase.pdb\6D54516506E95F4ABC3FBDAF3373F96D1\file.ptr - path not found 
SYMSRV:  RESULT: 0x80070003 
SYMSRV:  BYINDEX: 0x20 
         http://127.0.0.1:9094/home/apache/winsym 
         combase.pdb 
         6D54516506E95F4ABC3FBDAF3373F96D1 
SYMSRV:  UNC: D:\Windows Kits\Debuggers\x64\sym\combase.pdb\6D54516506E95F4ABC3FBDAF3373F96D1\combase.pdb - path not found 
SYMSRV:  UNC: D:\Windows Kits\Debuggers\x64\sym\combase.pdb\6D54516506E95F4ABC3FBDAF3373F96D1\combase.pd_ - path not found 
SYMSRV:  UNC: D:\Windows Kits\Debuggers\x64\sym\combase.pdb\6D54516506E95F4ABC3FBDAF3373F96D1\file.ptr - path not found 
SYMSRV:  HTTPGET: /home/apache/winsym/combase.pdb/6D54516506E95F4ABC3FBDAF3373F96D1/combase.pdb 
SYMSRV:  WinHttpSendRequest: 800C0057 
SYMSRV:  RESULT: 0x800C0057 
DBGHELP: combase.pdb - file not found 

I got "WinHttpSendRequest: 800C0057" after cdb tried to download symbol from my http server. It's totally ok if i call cdb from a Command Prompt.

I digged and found out:

When running from a Command Prompt, cdb uses WinINet to access internet resources.
When running from a Windows service, cdb uses WinHTTP to access internet resources.

But i found nothing about "WinHttpSendRequest: 800C0057"