Hi @omco77633670 ,
There are different versions of API you can use (v1.4 and v2.0) and depending on which you use, the requests look significantly different.
If you are using v2.0, please review the request in swagger, here. Custom events use the same request, and you can run the /metrics API first to get the ID... In this example, the ID is probably metrics/event7.
All the best