Turn on IncludeExceptionDetailInFaults (either from ServiceBehaviorAttribute or from the configuration behavior) on the server in order to send the exception information back to the client, or turn on tracing as per the Microsoft .NET Framework 3.0 SDK documentation and inspect the server trace logs.

I was getting an error while trying to deploy webservice

Turn on IncludeExceptionDetailInFaults (either from ServiceBehaviorAttribute or from the <serviceDebug> configuration behavior) on the server in order to send the exception information back to the client, or turn on tracing as per the Microsoft .NET Framework 3.0 SDK documentation and inspect the server trace logs.

This error occurs due to STS service not able to authenticate the request. A detailed solution to this problem is explained at the Microsoft blog

https://blogs.technet.microsoft.com/spjr/2018/06/18/sharepoint-troubleshooting-the-security-token-service-sts/


Add <serviceDebug includeExceptionDetailInFaults="True" httpHelpPageEnabled="True"/> to the file at \14\WebServices\SecurityToken/web.config like so

<configuration>
  <system.serviceModel>
    <behaviors>
      <serviceBehaviors>
        <behavior name="debug">
          <serviceDebug includeExceptionDetailInFaults="true" />
        </behavior>
      </serviceBehaviors>
    </behaviors>
    ...
  </system.serviceModel>
</configuration>