Today, I wanted to debug a CMS system. I remember that IIS was installed long ago on my work computer, but it wouldn't start, and even reinstallation didn't work. The issue was: an unexpected error 0x8ffe2740 occurred. Later, I found the solution:
**Cause:**
If there is a port conflict in the system, this situation may occur. By default, IIS uses port 80 for HTTP communication.