Estou com o seguinte problema ao realizar uma requisição utilizando o PUT, meu back-end utiliza PHP.

Meu código PHP:

//inicio PHP
header("Access-Control-Allow-Origin: *");
header("Access-Control-Allow-Headers: Origin, X-Requested-With, Content-Type, Accept");
header('Content-Type: application/json; charset=UTF-8');
header('Access-Control-Allow-Methods: POST, GET, PUT, OPTIONS'); 
//fim PHP

//TS //inicio TS

public put(metodo_api: string, dados) {
    console.log(JSON.stringify(dados));

    const httpOptions = {
      headers: new HttpHeaders({
        "Content-Type": "application/json"
      })
    };
    // JSON.stringify(dados)

    this._http
      .put(
        "http://meudominio.com/api/" + metodo_api,
        { id: 1 },
        httpOptions
      )
      .subscribe(
        val => {
          console.log("PUT call successful value returned in body", val);
        },
        response => {
          console.log("PUT call in error", response);
        },
        () => {
          console.log("The PUT observable is now completed.");
        }
      );
  }
// fim TS

Warning: Access to XMLHttpRequest at 'http://meu.dominio.com/api/clientes' from origin 'http://localhost:8100' has been blocked by CORS policy: Response to preflight request doesn't pass access control check: It does not have HTTP ok status. requisicoeshttp.service.ts:55

Error: HttpErrorResponse {headers: HttpHeaders, status: 0, statusText: "Unknown Error", url: "http://meudominio.com/api/clientes", ok: false, …} error: ProgressEvent {isTrusted: true, lengthComputable: false, loaded: 0, total: 0, type: "error", …} headers: HttpHeaders {normalizedNames: Map(0), lazyUpdate: null, headers: Map(0)} message: "Http failure response for http://meudominio.com/api/clientes: 0 Unknown Error" name: "HttpErrorResponse" ok: false status: 0 statusText: "Unknown Error" url: "http://meudominio.com/api/clientes"