nlog in netcore does not output Trace, Debug and Information log

When using nlog in .netcore application, I found out a very strange thing: When using VisualStudio to debug the application, the nlog works perfect. I set the minloglevel in nlog.config to Debug:

  <rules>
    <!--Skip Microsoft logs and so log only own logs-->
    <logger name="Microsoft.*" minlevel="Trace" writeTo="blackhole" final="true" />
    <!--All logs, including from Microsoft-->
    <!--<logger name="*" minlevel="Warn" writeTo="console" /> -->
    <logger name="*" minlevel="Debug" writeTo="applog" />
  </rules>

However, when deployed to server, the log only shows level equals or greater than Warning. I have also set the minlevel in program.cs file and it is still output Trace, Debug and Information log:

 .ConfigureLogging((host, builder) =>
 {
  host.HostingEnvironment.ConfigureNLog("nlog.config");
  builder.SetMinimumLevel(LogLevel.Debug);
 })

After lots of search, someone suggested to change the LogLevel in appsettings.json file as well. The original value is Warning. After I changed it to Debug, the application finally output Debug and Information logs.

  "Logging": {
    "IncludeScopes": false,
    "LogLevel": {
      "Default": "Debug"
    }