I had this exact issue, but I am on a clustered search head and clustered indexer environment. If you run the search command manually (go to Search Head -> Settings -> Searches, Reports, and Alerts -> App: Splunk App for CEF -> Run ) you get the same error as https://answers.splunk.com/answers/538377/splunk-app-for-cef-how-to-resolve-error-search-fac.html -- "Search Factory: Unknown search command 'cefout'".
To fix this I moved the bin folder and the commands.conf to the Splunk_TA_cefout app on the indexers and it resolved my issue.
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