I want to alert when there is communication error with license master.
I tried with index=_internal sourcetype=splunkd "failed to transfer rows*"
But want to know from splunk experts the query to know if there is any communication error.
What you are doing is correct.
Please find the below splunk documentation.
"To find out if a license slave has been unable to reach the license master, look for an event that contains failed to transfer rows in splunkd.log or in the _internal index."