Search By Landlot number not working

Previously, my project used https://developers.onemap.sg/publicapi/commonsvc/landlotsearch?searchVal=(landlot num)&token=(token value)&returnGeom=Y&getAddrDetails=N
to retrieve landlot information. However, this API seems like not working now.

Is there any alternative API that allow me to search by landlot number?

You should not use the mentioned API endpoint for your project.

Then what API should I use to search by landlotnumber?

The API is not opened for developer to use. You can contact our team at onemap[at]sla[dot]sg for your API interest.