Hi,

I am writing a C#.NET to send emails using Exchange Web Services APIs. I could find that the code works perfectly when I give the correct user name and password. But, if I give a wrong password on first attempt, the Autodiscover seldom Succeeds.

Here is my sample code:

try
{
	m_EWService = new ExchangeService(ExchangeVersion.Exchange2007_SP1);
	m_networkCredential = new NetworkCredential();

	GetCredentials(sMailbox, out m_networkCredential);

	m_EWService.Credentials = m_networkCredential;
	m_EWService.AutodiscoverUrl(m_networkCredential.UserName, RedirectionCallback);

}
catch (Exception ex)
{
	System.Console.WriteLine(ex.Message);
	ShowMessage(ex.HResult, ex.Message);
}

public static void GetCredentials(string serverName, out NetworkCredential networkCredential)
{
	CREDUI_INFO credui = new CREDUI_INFO();
	credui.pszCaptionText = "Please enter the credentails for " + serverName;
	credui.pszMessageText = "";
	credui.cbSize = Marshal.SizeOf(credui);
	uint authPackage = 0;
	IntPtr outCredBuffer = new IntPtr();
	uint outCredSize;
	bool save = true;
	int result = CredUIPromptForWindowsCredentials(ref credui,
												   0,
												   ref authPackage,
												   IntPtr.Zero,
												   0,
												   out outCredBuffer,
												   out outCredSize,
												   ref save,
												   0x1 /* Generic */);

	var usernameBuf = new StringBuilder(100);
	var passwordBuf = new StringBuilder(100);
	var domainBuf = new StringBuilder(100);

	int maxUserName = 100;
	int maxDomain = 100;
	int maxPassword = 100;
	if (result == 0)
	{
		if (CredUnPackAuthenticationBuffer(0, outCredBuffer, outCredSize, usernameBuf, ref maxUserName,
										   domainBuf, ref maxDomain, passwordBuf, ref maxPassword))
		{

			//clear the memory allocated by CredUIPromptForWindowsCredentials 
			CoTaskMemFree(outCredBuffer);
			networkCredential = new NetworkCredential()
			{
				UserName = usernameBuf.ToString(),
				Password = passwordBuf.ToString(),
				Domain = domainBuf.ToString()
			};
			return;
		}
	}

	networkCredential = null;
}

Can someone throw some light into how to make it working after the login failure;

• Moved by Kristin Xie Friday, March 13, 2015 5:58 AM move to appropriate forum

Have you tried correcting the credentials and trying again? There's nothing special with EWS you have to do.