If the relative path is not used, it is likely that the resource file access must go through the root directory of the server.
http://domain name/project name/folder
Similar to the above directory, this will cause many index.html files accessed from the root directory Nginx configuration to be in the loading state, and all resource files will report error 404
solution:
In package.json "build": "ng build", change to the following
"scripts": {
...
"build":"ng build --base-href ./",
...
},