But when I installed, the info said:  http://localhost:8080/iris/csp/sys/UtilHome.csp I am not sure why.

I also try with: http://localhost:8080/csp/sys/UtilHome.csp doesn't seem to resolve.

Then, I test with and without "pathPrefix" in settings.json, still the same. 
 

I got it. The problem was because I was using macOS 14 “Sonoma” and I didn't set up httpd server. I did install the httpd server before I installed InterSystems IRIS but I did know it needed to set up. I used this for server setting up: "https://discussions.apple.com/docs/DOC-250007792" and it worked. Thank for help, everyone.