Answer

PROBLEM

When trying to access parts of the GFI MailEssentials user interface, you get one of the following errors:

HTTP 404 Not Found Error

Could not communicate with middle layer

System.Web.HttpException: Session state can only be used when enableSessionState is set to true, either in a configuration file or in the Page directive at System.Web.UI.Page.get_Session() at ContentSecurity.Quarantine.Today3.Page_Load(Object  sender, EventArgs e)

ENVIRONMENT

• GFI MailEssentials 
• Microsoft SharePoint 3.0
• Microsoft SharePoint Portal Server 2007
• all supported environments

SOLUTION

Different solutions are provided for each version of Microsoft SharePoint. Please use the solution for your version of Microsoft SharePoint.

• Microsoft SharePoint Services Version 2.0 or Microsoft SharePoint Server 2003
• Microsoft SharePoint Services Version 3.0 or Microsoft SharePoint Server 2007    

Microsoft SharePoint Services Version 2.0 or Microsoft SharePoint Server 2003

There are two solutions to this issue. Only one of these solutions needs to be implemented to resolve the issue.

Solution 1:- Configure an exclusion for GFI MailEssentials in Microsoft SharePoint. Microsoft SharePoint and Microsoft SharePoint Portal Server need to be configured not to intercept requests to the GFI MailEssentials web application. Such requests need to be handled by Microsoft Internet Information Services (IIS). This can be done as follows:

1. Open Microsoft SharePoint Central Administration. (Start > Administrative Tools > SharePoint Central Administration)
2. In the Virtual Server Configuration area, click Configure virtual server settings
3. In the Virtual Server List tab, select the virtual server that you have GFI MailEssentials installed on
4. Under Virtual Server Management, select Define Managed Paths
5. In the Add a New Path section, type the name of the virtual directory that GFI MailEssentials is installed on, in the Path box. The default value is MailEssentials. 
6. Click on Excluded Path, and then click OK

After performing the above steps, open the GFI MailEssentials configuration, and try to access the "Today filter" in the Quarantine node. If the second error listed above is received, the GFI MailEssentials  web.config needs to be amended as follows:

1. Browse to the <...\GFI\MailEssentials\WwwConf\> directory.
2. Create a backup of web.config
3. Open web.config in notepad or another text editor
4. Find the line
   • <!-- add name="Session" type="System.Web.SessionState.SessionStateModule"/> -->
5. Remove the text in bold from the line above. The line should read:
   • <add name="Session" type="System.Web.SessionState.SessionStateModule"/>
6. Close web.config, and save the changes
7. Try to re-open the GFI MailEssentials configuration and access the 'Today Quarantine' filter to ensure that the issue is resolved

Note: Whenever GFI MailEssentials switchboard is used to change Virtual Directory, then an exclusion to the new Virtual Directory must be made. Important:Only the text marked in bold should be changed. The rest of the text should not be changed. Incorrect use of this file may result in malfunctioning of the application. Should you notice any strange behavior, you should revert to the backed up web.config.

Solution 2:- Install GFI MailEssentials to a Web Site where Microsoft SharePoint is not installed. An alternative to creating an exclusion for GFI MailEssentials in Microsoft SharePoint is to install GFI MailEssentials to a Web Site where Microsoft SharePoint is not installed.

1. Create a new website in Microsoft Internet Information Services (IIS), and make sure that Microsoft SharePoint is not installed on this website
2. Use the GFI MailSecurity or MailEssentials switchboard, to change the website from the website in which the application is installed with to the one that does not have Microsoft SharePoint installed on it
3. Make sure that web.config found in the wwwconf folder is the original one, and no changes have been done to it
4. Open the GFI MailEssentials configuration.

Notes:

• Information on how to create a new website in Microsoft Internet Information Services (IIS) can be found at: http://support.microsoft.com/kb/816576/en-us.
• If an existing website that does not have Microsoft SharePoint installed on it exists, it is possible to re-use it, rather then create a new one.

Microsoft SharePoint Services Version 3.0 or Microsoft SharePoint Server 2007

There are two solutions to this issue. Only one of these solutions needs to be implemented to resolve the issue.

Solution 1:- Remove the Wildcard Application Mappings for GFI MailEssentials Microsoft SharePoint and Microsoft SharePoint Portal Server need to be configured not to intercept every request before the requested page is sent to the GFI MailEssentials web application. Such requests need to be handled by Microsoft Internet Information Services (IIS). This can be done as follows:

1. Open the Internet Information Services (IIS) Manager.
2. Browse to Websites and locate the website used by GFI MailEssentials
3. Right click the GFI MailEssentials virtual directory and select Properties.
4. In the Virtual Directory tab click the Configuration button.
5. Remove any entries from the Wildcard application maps section.
6. Click on OK to apply the changes.

Notes:

• The procedure above needs to be repeated every time GFI MailEssentials is installed as a fresh installation.

Solution 2:- Install GFI MailEssentials to a Web Site where Microsoft SharePoint is not installed. An alternative to creating an exclusion for GFI MailEssentials in Microsoft SharePoint is to install GFI MailEssentials to a Web Site where Microsoft SharePoint is not installed.  

1. Create a new website in Microsoft Internet Information Services (IIS), and make sure that Microsoft SharePoint is not installed on this website
2. Use the GFI MailEssentials switchboard, to change the website from the website in which GFI MailEssentials is installed with the one that does not have Microsoft SharePoint installed on it
3. Make sure that web.config found in the wwwconf folder is the original one, and no changes have been done to it
4. Open the GFI MailEssentials configuration.

Notes:

• Information on how to create a new Web site in Microsoft Internet Information Services (IIS) can be found at: http://support.microsoft.com/kb/816576/en-us.
• If there is an existing website that does not have Microsoft SharePoint installed on it, it is possible to use it, rather then create a new one.

More Information: See http://support.microsoft.com/kb/828810/en-us?spid=11373&sid=210 for more information on How to enable an ASP.Net application to run on a SharePoint virtual server 

CAUSE

Microsoft SharePoint tries to intercept all requests to the Web Applications installed in the same website as Microsoft SharePoint.