Api acknowledge problem

I am trying to acknowledge a service problem with the API using postman and i see an error using the same query mentioned in the doc.

example in https://icinga.com/docs/icinga-2/latest/doc/12-icinga2-api/#acknowledge-problem

getting the above error 404

where as if if change the query a bit it works .

is the documentation outdated ? Is the acknowledge query really changed in 2.12 ?

icinga2 - The Icinga 2 network monitoring daemon (version: 2.12.1-1)