Angular HTTP API calls timeout intermittently?

As the query implies, API calls being blocked occasionally and doesn't return the response but time out. Not sure what's going on. I did debug to check whether anything wrong with the server side implementation and I have had found that the API request hasn't hitting the server side. Do any one face this before. If then, pl. suggest me any workaround.

Sample Code:

 this.userProvider.getProfileDetails()
      .subscribe((data: IProviderProfile) => {
        },
        (err: INetworkError) => {
        });

Provider

getProfileDetails(): Observable<any> {
        return this.apiProvider.authJsonGet(this.config.apiEndpoint + this.config.profileDetailsUrl);
}

public authJsonGet(url: string, params?: URLSearchParams): Observable<any> {
        return this.intercept(url, RequestMethod.Get, this.httpGet(url, params));
  }

Don't be confused, were intercept is a custom function which do handle session expire, no big deal inside it.

Thanking you.