Error message when you try to connect to a Web site that is hosted in Internet Information Services (IIS): "Service unavailable"

When you try to connect to a Web site that is hosted in Microsoft Internet Information Services (IIS) 6.0, you receive the following error message:When this issue occurs, no Error events are logged in the Application log on the Web server. However, an error message that resembles the following is logged in the Httperr.log file on the Web server:

This issue occurs if the following conditions are true:

• You set the connection limit for the Web site to a specific number of concurrent connections.
• The number of concurrent connections to the Web site exceeds the connection limit that you set.

To resolve this issue, use one of the following methods.

Note In Internet Information Services 7.0, you can set connection limits in the Connection Limits section of a site's Advanced Settings window in Internet Services Manager.

Method 1

Increase the connection limit for the Web site. To do this, follow these steps:

1. Click Start, point to All Programs, point to Administrative Tools, and then click Internet Information Services (IIS) Manager.
2. Expand ComputerName, and then expand Web Sites.
3. Right-click the Web site that you want to configure, and then click Properties.
4. Click the Performance tab.
5. Under Web site connections, click Connections limited to, and then type the connection limit that you want to set.
6. Click OK, and then exit IIS Manager.

Method 2

Set the connection limit for the Web site to an unlimited number of concurrent connections. To do this, follow these steps:

1. Click Start, point to All Programs, point to Administrative Tools, and then click Internet Information Services (IIS) Manager.
2. Expand ComputerName, and then expand Web Sites.
3. Right-click the Web site that you want to configure, and then click Properties.
4. Click the Performance tab.
5. Under Web site connections, click Unlimited.
6. Click OK, and then exit IIS Manager.

For more information about how to set the connection limit in IIS 6.0, see the "Limiting Connections" topic in IIS 6.0 Help. For more information about how to access IIS 6.0 Help, click the following article number to view the article in the Microsoft Knowledge Base: