Some versions of 4.1 shipped with a forwarder license that expired too soon. You can get a forwarder licenseby downloading and unpacking the most recent 4.1 release.
Don't try to get it from 4.2, as it does not come with (or require) a separate forwarder license.
Verify the forwarder is not indexing AND forwarding.
From the GUI, you would follow these steps...
This is equivalent to outputs.conf setting:
indexAndForward = false
if it doesnot index data it doesnot need license.
You just need to do the following:
# copy %SPLUNK_HOME%\etc\splunk-forwarder.license %SPLUNK_HOME%\etc\splunk.license b. Nix: # cp $SPLUNK_HOME/etc/splunk-forwarder.license $SPLUNK_HOME/etc/splunk.license