El siguiente código angular switchMap no funciona, no estoy seguro de qué error cometí. Bajo la segunda llamada de API de switchMap que no activa '/upload/file'

 zip( this.service.submitForm(formValue), this.service.upload(fData) ).subscribe( ([submitForm, upload]) => { if (submitForm === 'success' && upload === 'Ok') { //Redirect confirmation page } }, (err) => { console.log(err, 'ERORORO'); } ) //Service code upload(formData): Observable <any> { return this.sessionService.keepAlive().pipe( switchMap(data => { let token = data.jwtToken; console.log(token, 'TOKEN SESSION'); // getting output as Bearer xyz // with formData as req const request_config = { headers: { "Authorization": token } }; console.log("REQUEST CONFIG", request_config); // getting output return this.http.post < any > ( '/upload/file', formData, request_config ).pipe( // this is not working map((res) => { console.log(res, 'RESPONSE'); return res.status; }), catchError((error: HttpErrorResponse) => { throw error; }) ) }) ) }