splunk add-on NewRelic Authentication Error

[jeski]

Hi, weve installed the splunk newrelic add-on ver 2.10 and am seeing oddness in the splunk_ta_new_relic_new_relic_account_input.log

What have we done wrong?

Here's the line:
AuthenticationError: Autologin succeeded, but there was an auth error on next request. Something is very wrong.

[tomm_splunk]

This is generally a sign that the HTTP Authentication has failed. Please check that you've entered the proper API Key.

It might help to test from the command line first using curl:
curl -X GET ’https://api.newrelic.com/v2/applications.json' -H ‘X-Api-Key:[your API Key]’ -i

of you can generate curl statement for your account here:
https://rpm.newrelic.com/api/explore/applications/list