how to use angular service inside rxjs retryWhen method

I am making the http service calls 3 times when i get 401 error using the retryWhen method form Rxjs operators. My problem is when i get 401 error as status i need to make other service to get the token updated and then re-try the http service call 3 times . I am unable to use service inside retryWhen call back method as it always showing this as undefined . Can you please provide me solution for this.

return this.http.get(url, this.getOptions(options)).retryWhen(errors => {
return errors.mergeMap((error) => {
console.error('error status....', this, error, error.status);
if (error.status === 401) {
// i need to make other service call here
this.httpPollingService.updateToken(); // unable to call this call.
return Observable.of(error);
} else {
return Observable.throw(error);
}
}).delay(5000).take(2);
});

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