I am trying to test my splunk HEC token by ending an event to my splunk cloud instance, How can i verify i have the right HEC host name?

I am using the curl command to send an event to Splunk cloud, but I am getting timeout errors and host not found errors. I believe it is the host name that is the problem.

I have tried the "Server Name" from the About section on our Splunk cloud UI. I have also tried pinging this server name but that didn't work.

I have tried the same with the URL in my Splunk cloud UI browser, no response from that.

curl -v -k https://input-??????:8088/services/collector -H "Authorization: Splunk #######" -d '{"sourcetype": "_json", "event": "Hello, world!"}'

I expect to see something like {"text": "Success", "code": 0} and the event in my Splunk cloud UI.