I have followed the installation and configuration guide to get Splunk Light working and now I am at the point of adding a data source.
I get the same generic messsage (see screenshot) when I try to add a forwarder or setup syslog via the Monitor button.
There a lot of posts around about roles but as this is Splunk Light you only have the admin role to work with.
Am I missing something obvious?
Based on the error message, this does seem to be a matter of your role not having the necessary permissions to add data to the instance. Sorry if this is a basic question, but are you sure you are using Splunk Light? The screen shot appears to be Splunk Enterprise.