Hi Chooi,
I encountered this same issue. The curl code snippet provided by ServiceNow's REST API Explorer doesn't work (at least it didn't for me).
When using the REST API Explorer (in Geneva), it works fine with the credential I configured. The credential I created was granted only the ITIL and snc_read_only roles, since I only needed it to do a GET. When attempting to use the curl snippet provided by the API Explorer, however, I would constantly get the following error:
{"error":{"detail":"Required to provide Auth information","message":"User Not Authenticated"},"status":"failure"}
It wasn't until I base64 encoded the username:password, and defined the Authorization header that I was able to get a successful curl result from ServiceNow using curl.
So the code snippet is a good start but is non-functioning until you base64 encode the username:password pair.
Here's an example curl command that worked for me where "bXl1c2VybmFtZTpteXBhc3N3b3Jk" is the base64-encoded string "myusername:mypassword" (without quotes). You can use postman to encode your username:password pair.
curl "https://myinstance.service-now.com/api/now/table/incident?sysparm_limit=1&sysparm_display_value=true&sysparm_fields=number%2Cshort_description%2Ccaller_id&sysparm_view=default" --request GET --header "Accept:application/json" --header "Authorization:basic bXl1c2VybmFtZTpteXBhc3N3b3Jk'
I know this is pretty late, but I hope this helps,
-Joe
