The error is:
[HTTP 500] [HTTP 409] App "Splunk_TA_isc-bind" already exists; use the "-update true" argument to install anyway
I tried tar a tgz file into etc/apps/ and reload Splunk (version 6.5 but expired enterprise so free license ). I still faced the same error 😞
Please help 🙂
manage to solve it using
splunk app install splunk-add-on-for-isc-bind_100.tgz -update true
Please accept the answer to help future readers.