Try debugging the situation. Have you looked at the network traffic? Is there a DNS request made? Are there any replies?
A common trap is that a program/system has a local cache. For example, your browser might not make a DNS request for every HTTP request. It will typically do it once and reuse the result on consecutive HTTP requests.
Also, DNS spoofing does work with HTTPS. Or better, HTTPS is something separate of DNS. DNS doesn’t work with HTTPS in a similar way as putting your own house number on a neighbour’s house doesn’t allow you to enter the neighbour’s house with your own key. ;)