I am seeing the below issue,
Httpsconnectionpool(host='phantomdev..com', port=XXX): max retries exceeded with url: /rest/ph_user?include_automation=true&filter_token_key='' (caused by sslerror(sslerror(1, u'[ssl: certificate_verify_failed] certificate verify failed (_ssl.c:741)'),))
i was trying to disable the ssl, which was in README, was not able to succeeded because of i haven't seen those conf.
Did the link and advice from @ansusabu and/or @WalshyB help you get this solved?
You can use the curl command given in README for disabling ssl
https://docs.splunk.com/Documentation/PhantomApp/2.7.5/Install/ConfigureCerts, see "Manage HTTPS certificate validation using configuration files", did you do those steps followed by a restart?