An administrator has just installed a web server for the company's Internet site. After bringing the system online, customers notify the administrator that they cannot connect to the server. The administrator tests the web server from a workstation and can access the website. The customers continue to report issues. Which of the following is the MOST likely reason for this?（）

• A、The server's firewall is misconfigured.
• B、The server's timeout feature is set incorrectly.
• C、The web server was not installed properly.
• D、The company firewall is misconfigured.