How to register webhook for Jira Cloud Application

[Karthik dharmalingam]

I have two questions related to registering webhooks,

1)In Jira Software(cloud), I couldn't register webhooks using Rest API in OAuth 2.0 authentication.

I tried the following Rest apis with post data and also tried sending the access token,

https://dkarthik29115.atlassian.net/rest/api/2/webhook

https://dkarthik29115.atlassian.net/rest/webhooks/1.0/webhook

https://api.atlassian.com/ex/jira/380400c8-e207-440a-a26e-7b6dfa86bbf3/rest/api/2/webhook

Got the same error, "Client must be authenticated to access this resource."

I got the below link in one of the error response, is it solved now?

https://ecosystem.atlassian.net/browse/ACJIRA-1632

There is a way to register using App Token, but I need to register only using Rest API. 

Is there any hidden Rest API used to register webhooks in OAuth 2.0 authentication? 

2) In Jira Software Server, while registering webhook is it possible to give the URL with the port other than 8080?

I tried with other port(8443) but I didn't get the webhook notification. Is it a behavior?