How to add another exception rule in Angular?

Question

Before showing my problem I would like to inform you that my form is able to insert records in the database, I created an exception in my java API, the error message in the figure below is expected, however my Angular project is only able to issue generic exceptions, and I need to create an error message for this exception below and I don’t know how to do.

Watch the image:

This is the code responsible for taking the generic exception, and it is this code that you must modify in order to be able to generate a message for the specific exception with the name of NomeEstiloJaCadastradoException

import { Injectable } from '@angular/core';

import { ToastyService } from 'ng2-toasty';

@Injectable()
export class ErroHandlerService {

  constructor(private toasty: ToastyService) { }

  handle(errorResponse: any) {
    let msg: string;

    if (typeof errorResponse === 'string') {
      msg = errorResponse;
    } else {
      msg = 'Erro ao processar serviço remoto. Tente novamente.';
      console.error('Ocorreu um erro', errorResponse);
    }

    this.toasty.error(msg);
  }

}

I know I found a model similar to mine on the internet, but I don’t know how to make this change to the system take the name exception NomeEstiloJaCadastradoException, and I need help

Model

MY REPOSITORY