The 404 is typically returned when you try to retrieve an entity that does not (yet) exist. Are you using GET http method? If you want to store an entity, you need to use PUT.
Can you share your code? That way I can see what you are trying to do and give you proper pointers.
The url of your instance seems a bit off, did you change that in this example? Because normally, Jira Cloud instances would have a https://<NAME>.atlassian.net base url. You might also want to switch to version 3 of the api /rest/api/3/.
Also, it seems like you are using Basic authentication (username/password). That authentication method is no longer supported, you should use API tokens. In addition, maybe you should remove the user credentials from your example, as this is a public forum
API 3 is still in beta, I wouldn’t recommend switching to it, unless you need to work with ADF.
This message is returned only when accessing app properties. You need to be authenticated with JWT as your app to do it. Regular requests with curl and basic auth as yourself won’t work.
So… maybe change the documentation pages? As V3 is now the default API to which the documentation refers (https://developer.atlassian.com/cloud/jira/platform/rest/). The comment about the API being in BETA is not really visible and it is only listed after the page reads
This documentation is for version 3 of the Jira Cloud platform REST API, which is the latest version.