Error connecting to Exchange Server - "Function evaluation timeout"

Aspose.Email Product Family
1

Hi,

I’m trying to connect to a External Exchange Server using the following code:

NetworkCredential cred = new NetworkCredential(“username”, “pass”, “domain”);
client = new Aspose.Network.Exchange.ExchangeClient(“ServerAdress”, cred);

WebProxy prox = new WebProxy(“10.0.0.1”, 8080);
prox.Credentials = new NetworkCredential(“ProxyUsername”, “ProxyPassword”,“ProxyDomain”);
prox.BypassProxyOnLocal = true;

client.Proxy = prox;

but after this when I debug the variable “client” it returns “Function evaluation timeout”.

The Exchange Server is a 2003 Exchange Server with a self-signed certificate. The variable “ServerAddress” I’m using is something like
"https://SERVERNAME/exchange/USERNAME@DOMAIN/Inbox/"

I tried the same code using our company Exchange Server and it works fine but only inside our Work Network.

Any ideas on where’s the problem lies?

Tkz

2

After a few more tests I can connect well to our company Exchange Server inside and outside our Work Network.

Reading the IP packages when trying to connect to the external Exchange Server:

-> OUR IP ----- DEST IP | SSL | CLIENT HELLO


->DEST IP ----- OUR IP | TLSv1| SERVER HELLO, CHANGE CHIPHER SPEC, ENCRYPED HANDSHAKE MESSAGE


->OUR IP ----- DEST IP | TCP | [ACK] Seq=154 Ack=123 Win=65398 Len=0


->OUR IP ----- DEST IP | TCP | [FIN, ACK] Seq=154 Ack=123 Win=65398 Len=0


->DEST IP ----- OUR IP | SSL | [ACK] Seq=123 Ack=155 Win=65382 Len=0


->DEST IP ----- OUR IP | SSL | [FIN, ACK] Seq=123 Ack=155 Win=65382 Len=0


3

Hi,

Was the problem resolved during your testing? If not, is there any exception that occurs? Could you please copy the stack trace here.

4

No. Only the problem accessing our company Exchange server.

The problem accessing the external Exchange Server still happens. I found out that it’s probably because the self-signed certificate of the external Exchange Server doesn’t have a Organizational Root Certificate thus I can’t install the certificate in my Trusted Root Authority.

The bug ID: 13473 could solve this problem. Got any workaround?

Tkz

5

Hi,

Could you please try the following workaround to avoid certificate issues.

Add below line in some init() method or constructor of the class where you are using ExchangeClient.

ServicePointManager.ServerCertificateValidationCallback += RemoteCertificateValidationHandler;

And then, add the following method in the class:

private bool RemoteCertificateValidationHandler(object sender, X509Certificate certificate, X509Chain chain, SslPolicyErrors sslPolicyErrors)
{
return true; //ignore the checks and go ahead
}

6

Tkz.

That works to bypass the certificate but now I get the 440 error - Login Timeout.

I use the same ServerAddress, Username, Password and Domain on browser and it works. I’m only using the following code to connect

NetworkCredential cred = new NetworkCredential(config.Username, config.Password, config.Domain);
client = new Aspose.Network.Exchange.ExchangeClient(config.ServerAdress, cred);

Do I need to set de CookieContainers like in the post

client.CookieContainer = new CookieContainer();
client.CookieContainer.Add(AuthenticateSecureOWA(serverName, domain,
userID, password));

7

Hello, after contacting the external Exchange Server Administrators I found that:

  • Form-based Authentication (FBA) is not active in front-ends.
  • To login in the domain it uses the Kerberos protocol.
  • OWA by ISA Server access (SSL)

for what I could see in the internet we need to have FBA active, right?


Tkz