Forum Discussion
RoyMGiv
Jun 05, 2024Copper Contributor
Unable to initialize ExchangeService instance
I am trying to write a program that checks for changes in a mailbox's calendar every time it runs and updates a database. My problem begins at the very top of the assignment when I initialize the ExchangeService instance and any function I try to run on it returns
The request failed. The remote server returned an error: (401) .
I initialized it like this:
private static void initExchangeService()
{
m_ExchangeService = new ExchangeService();
m_ExchangeService.UseDefaultCredentials = true;
m_ExchangeService.KeepAlive = true;
string domain = ConfigurationManager.AppSettings["Domain"];
m_ExchangeService.Credentials = new System.Net.NetworkCredential(CREATOR_MAIL, CREATOR_PASSWORD, domain);
m_ExchangeService.ImpersonatedUserId = new ImpersonatedUserId(ConnectingIdType.SmtpAddress, CREATOR_MAIL);
if (string.IsNullOrEmpty(EXCHANGE_URL))
{
m_ExchangeService.AutodiscoverUrl(CREATOR_MAIL);
}
else
{
m_ExchangeService.Url = new Uri(EXCHANGE_URL);
}
writeToLog($"Initialized exchange service for {CREATOR_MAIL}", MESSAGE);
}
The mailbox I am trying to access has 2-step authentication disabled and I worked with the system admin to ensure on our end that I have the permissions I need to run this but any address I try (even non real ones) returns the same error.
I'd love some help figuring out what the problem is.
- zeeshandurrani965Copper ContributorThe 401 error suggests an authentication issue. Check the following:
Ensure CREATOR_MAIL and CREATOR_PASSWORD are correct.
Set UseDefaultCredentials to false.
Confirm the EXCHANGE_URL is correct or use AutodiscoverUrl with a valid callback.
Verify you have the necessary permissions for impersonation.
Here's a refined initialization:
csharp
Copy code
private static void initExchangeService()
{
m_ExchangeService = new ExchangeService();
m_ExchangeService.UseDefaultCredentials = false;
m_ExchangeService.KeepAlive = true;
string domain = ConfigurationManager.AppSettings["Domain"];
m_ExchangeService.Credentials = new System.Net.NetworkCredential(CREATOR_MAIL, CREATOR_PASSWORD, domain);
m_ExchangeService.ImpersonatedUserId = new ImpersonatedUserId(ConnectingIdType.SmtpAddress, CREATOR_MAIL);
m_ExchangeService.Url = string.IsNullOrEmpty(EXCHANGE_URL) ? new Uri(EXCHANGE_URL) : m_ExchangeService.AutodiscoverUrl(CREATOR_MAIL);
writeToLog($"Initialized exchange service for {CREATOR_MAIL}", MESSAGE);
}
Ensure the network allows the connection and there's no firewall blocking it.