When you encounter problems with cloud discovery, the first thing that you see may be licensing errors in the Manage > Discovery UI.
If the credential test was unsuccessful, ensure that you copied the secret access key correctly. Also, you should ensure that the appliance time is no further than five minutes of the time AWS is using. See Time setting for more information.
The BMC Discovery appliance must be able to access AWS using https (port 443).
You should ensure that your appliance time is synchronized using NTP. If you do not use NTP, you must ensure that the time is no further than five minutes of the time AWS is using. AWS uses timestamped authentication and any discrepancy can result in authentication failures which might be difficult to diagnose.