I am trying to call the dummy API from SPFX, but I am getting an error, `Failed to fetch`,

      this.context.httpClient
      .get("http://dummy.restapiexample.com/api/v1/employees", HttpClient.configurations.v1)
      .then((res: HttpClientResponse): Promise<any> => {
        alert("");
        return res.json();
      })
      .then((data: any): void => {
        alert("");
        // Process your data here
      }, (err: any): void => {
        // Handle error here
      });

How can I fix this problem?