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Project Server 2007 Add-in for Outlook login problems

September 4, 2008

In setting up an Office Project Server 2007, you need the Outlook add-in in order to sync your tasks or calendar between Outlook and Project Web Access. The problem is I and several others out there were having a heck of a time getting authentication to work.

First, I would get an error aboout an invalid URL, even though I know the URL works perfect in a browser and in Project Professional. The error would be “The Project Server URL seems to be invalid. Please check the spelling of the Project Server URL.”  There are two fixes for this.  Enable Anonymous Access to the root of the project website in IIS (this is safe – users will still need to authenticate to gain access), or enable Windows Authentication and make sure your computer’s username and password match your server’s username and password.  To verify everything is working, you should be able to browse to and get a description about the LoginForms web service.

Once that problem was solved, I would get errors such as “Login Failed” or “The server was successfully contacted, but the login attempt failed.” Using the IIS Logs, I noticed that when you configure the add-in to use a Project Server Account, it is using this URL:


But when you use a Windows Account, it uses this URL:


So, it seems that when “Use a Project Server Account” is selected it is actually trying to use Forms Authentication, which is disabled by default. That gives you two options – enable Forms Authentication, or make sure your username and password match between the computer and the server.  If your username and password match, then check the “Use Windows User Account” option.

Update: I’ve also discovered another strange behavior. After a reboot, I get an authentication error. But, after using Internet Explorer and log in to Project Web Access, then I can use the plug-in in Outlook. Seems like a bug to me.

Update 2: Got it working, finally. The documentation says to put your Project Web Access URL into your Internet Explorer’s Trusted Sites security zone. It needs to go into your Local Intranet security zone. This allows for Integrated Authentication for fully-qualified websites (effectively, any URL with a dot in it). Second, you need to un-check Enable Protected Mode for the Local Intranet security zone. Now all is working and I have some happy customers.

Update 3: Not so fast. I had to put Project Web Access URL back in the Trusted Sites zone, otherwise Project Pro doesn’t like it. But this time I adjusted the security of the zone and checked "Automatic logon with current username and password". I also had to go back and disable anonymous authentication in IIS.

This plugin is just a mess. Clearly not much thought was put into the development of it.

Filed under: Microsoft | Comments (4)


  1. Rikky October 19, 2008 @ 7:53 pm

    Now this some great info!!! Thanks a lot!

  2. Michael October 28, 2008 @ 4:36 am

    Thank you. I’m still not even sure where you found this documentation you mentioned, but this did the trick for me.

  3. Nathan December 3, 2008 @ 10:06 am

    Thanks you. This saved our team much time

  4. Julio March 12, 2009 @ 7:11 am

    Totally agree with this “This plugin is just a mess. Clearly not much thought was put into the development of it.”, I use it with Microsoft Outlook 2003. When you close the email client and you open it (fast) again you will get most of the time connection errors with project server.
    This connection errors are so frustrating because if you open a task you can’t register time. Closing and opening again the email client it’s mandatory.
    My problem is that my boss loves the idea of registering the time from outlook. This lack of development has become a nightmare to me