Error: Your Microsoft Exchange Server is Unavailable

 

PROBLEM: You are unable to connect to the Exchange server, receiving a "Your Microsoft Exchange Server is Unavailable" error message.

There are several possibilities for seeing this error message:

  • Connectivity issue – Outlook isn't configured correctly and is unable be able to create a connection to the hosted Exchange server.

  • Port 135 is blocked - In response to the MS Blast worm that spread rapidly across the internet in 2003, numerous ISP's across the country have blocked port 135 to mitigate the spread of the worm. This worm exploits a vulnerability for the RPC process on port 135. Unfortunately, this is the same port used by Microsoft Outlook and the Microsoft Exchange servers to communicate

  • Registry settings for RPC client protocols may be corrupt


Connectivity Solutions

From your browser go to Outlook Web Access (OWA). If you get a pop-up window asking for your username and password, click "Cancel" and do the following:

  • Open a command prompt window.

  • Type telnet mailXXX 135 and click Enter. Replace the X's in "mailXXX" with the name of your mail server. You can find this information by going to Control Panel > Users > Outlook Setup. The name of your mail server is in the Exchange Server field.

  • The command prompt window should clear all text in the window and you should see the cursor blinking in the upper right-hand corner.


If the cursor isn't blinking it's possible that your company's firewall or your IPS's routers are blocking the connection. Please contact your system administrator to check if your company firewall is blocking outgoing port 135 TCP connections. If that is not the case, please contact your ISP to request that they unblock port 135 TCP for you. If they refuse please contact us to be setup for VPN access.

If you did not get a login dialog box when logging into OWA:

  • Open a command prompt window.

  • Type ping mailXXX and click Enter. Replace the X's in "mailXXX" with the name of your mail server. You can find this information by going to Control Panel &bt; Users > Outlook Setup. The name of your mail server is in the Exchange Server field.

  • After you click Enter you should return a message of "Pinging MAILXXX with 32 bytes of data:" If you do not see this message please re-run the setup software.


Port 135 Solutions

  1. Ask your ISP to unblock port 135 from their routers and firewalls. If they're hesitant about unblocking it, ask them to unblock it only for your IP. We have found that most business ISPs will do this for our customers.

  2. Access your entire Outlook mailbox via the web using WebMail. From any page on our website click on "Log In", then "Outlook Web Access".

  3. Use Virtual Private Networking (VPN) to connect to the Exchange server. This does involve making changes to your computer and can be inconvenient. If your ISP refuses to unblock the port, please follow instructions here to setup VPN access.


Registry Settings for RPC Client Protocols May be Corrupt Solution

Re-install TCP/IP:

  • Windows XP (Repair TCP/IP):
    • Click Start.
    • Click Run.
    • In the text box, type "cmd" (without the quotes) and click OK.
    • A new command prompt window will open. Type: "netsh int ip reset c:\resetlog.txt" (without the quotes), and press ENTER.
    • Type "exit" and press ENTER.
    • Restart your computer.
    • Setup Outlook and verify that it works correctly.

  • Windows 2000 (Uninstall and reinstall TCP/IP):
    • Log on as the local administrator.
    • Close all open programs, and then disable any anti virus program.
    • Right-click My Network Places on your desktop and select Properties.
    • Right-click Local Area Connection and select Properties.
    • Click Internet Protocol (TCP/IP), and select Uninstall.
    • You receive the prompt to uninstall TCP/IP, click Yes.
    • Restart your PC.
    • Log on as the local administrator.
    • Right-click My Network Places on your desktop and select Properties.
    • Right-click Local Area Connection and select Properties.
    • Click Install, and select Protocols.
    • Click Add.
    • Click Internet Protocol (TCP/IP), then click OK.
    • Click Close in the Local Area Connection Properties dialog box, then restart your computer.
    • Setup Outlook and verify that it works correctly.