We have setup an env with 3 search heads, 1 heavy forwarder and 3 indexers, then installed App and Add-on on search heads, only add-on on forwarder,and then connect remote add-on by target_helper.py on search heads.
After setup, we create a customized index in Setting -> Indexes menu on heavy forwarder, after a short while try to add a data input in App->Configure and we successfully find our customized index in New Input page.
Could you pls check the connection status between your remote target and each search head? Just run command below on your search head:
./splunk cmd python ../etc/apps/splunk_app_aws/bin/cli/targets_helper.py -get -username -password
And make sure you just create indexes with same name and assign them to same App name both on heavy forwarder and indexers, not search head.
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