Hi,
Looks like only latest 3 Simulator Images are available -9.7,9.6 & 9.5. NetApp site has been upgraded recently, so the old link now automatically re-directs to the new tools url, but I am not sure if it's possible to access old URL.
Anyway, any reason for Ontap 9.4 Simulator ? Are you trying to test any scenario specific to Ontap 9.4 ?
You can try this workaround:
1) Install 9.5 Simulator image.
2) Download 9.4 Production Image.
https://mysupport.netapp.com/site/products/all/details/ontap9/downloads-tab/download/62286/9.4/downloads
3) Get the 9.4 Image on the Simulator Node.
4) Follow the standard system node revert-to procedure to downgrade from 9.5 to 9.4.
Reverting an ONTAP cluster: (Obviously not all steps apply to Simulator, but the procedure works).
https://docs.netapp.com/ontap-9/index.jsp?topic=%2Fcom.netapp.doc.dot-cm-ug-rdg%2FGUID-1F953088-E84E-4437-A599-72C11D015757.html
Thanks!