Angular 的Http失败响应（未知url）

我想在Apache服务器的子目录中运行Angular应用程序。我在.htaccess文件中尝试了此配置：

<IfModule mod_rewrite.c>
  Options Indexes FollowSymLinks
  RewriteEngine On
  RewriteBase /admin/
  RewriteRule ^index\.html$ - [L]
  RewriteCond %{REQUEST_FILENAME} !-f
  RewriteCond %{REQUEST_FILENAME} !-d
  RewriteRule . index.html [L]
</IfModule>

其他页面工作正常。你能给我一些建议如何解决这个问题吗

errors-handler.ts:15 Error: Uncaught (in promise): HttpErrorResponse: {"headers":{"normalizedNames":{},"lazyUpdate":null,"headers":{}},"status":0,"statusText":"Unknown Error","url":null,"ok":false,"name":"HttpErrorResponse","message":"Http failure response for (unknown url): 0 Unknown Error","error":{"isTrusted":true}}
    at resolvePromise (zone.js:814)
    at resolvePromise (zone.js:771)
    at zone.js:873
    at ZoneDelegate.push../node_modules/zone.js/dist/zone.js.ZoneDelegate.invokeTask (zone.js:421)
    at Object.onInvokeTask (core.js:3811)
    at ZoneDelegate.push../node_modules/zone.js/dist/zone.js.ZoneDelegate.invokeTask (zone.js:420)
    at Zone.push../node_modules/zone.js/dist/zone.js.Zone.runTask (zone.js:188)
    at drainMicroTaskQueue (zone.js:595)
    at ZoneTask.push../node_modules/zone.js/dist/zone.js.ZoneTask.invokeTask [as invoke] (zone.js:500)
    at invokeTask (zone.js:1540)