Problem with setup wizard error 500

[gsimeuncevic]

I have a problem with setup wizard showing up for Splunk Add-on for Symantec Endpoint Protection.
Tried on standalone Splunk test instance version 7.2.6.

I got this errors:

12-13-2019 16:13:31.828 +0100 ERROR SetupAdminHandler - Error while fetching url=/servicesNS/nobody/Splunk_TA_symantec-ep/symantec_ep_setup/symantec_ep_script/symantec_ep_script/?_strict=true;search=%20eai%3Aacl.app%3D%22%22%20OR%20eai%3Aacl.app%3D%22Splunk_TA_symantec-ep%22
12-13-2019 16:13:31.818 +0100 ERROR ScriptRunner - stderr from '/opt/splunk/bin/python /opt/splunk/bin/runScript.py setup':    File "/opt/splunk/etc/apps/Splunk_TA_symantec-ep/bin/splunktalib/ca_certs_locater.py", line 60, in _fallback
12-13-2019 16:13:31.818 +0100 ERROR ScriptRunner - stderr from '/opt/splunk/bin/python /opt/splunk/bin/runScript.py setup':    File "/opt/splunk/etc/apps/Splunk_TA_symantec-ep/bin/splunktalib/ca_certs_locater.py", line 50, in _get
12-13-2019 16:13:31.818 +0100 ERROR ScriptRunner - stderr from '/opt/splunk/bin/python /opt/splunk/bin/runScript.py setup':    File "/opt/splunk/etc/apps/Splunk_TA_symantec-ep/bin/splunktalib/ca_certs_locater.py", line 30, in get   
12-13-2019 16:13:31.818 +0100 ERROR ScriptRunner - stderr from '/opt/splunk/bin/python /opt/splunk/bin/runScript.py setup':    File "/opt/splunk/etc/apps/Splunk_TA_symantec-ep/bin/splunktalib/httplib2_helper/httplib2_py2/httplib2/certs.py", line 35, in where  
12-13-2019 16:13:31.818 +0100 ERROR ScriptRunner - stderr from '/opt/splunk/bin/python /opt/splunk/bin/runScript.py setup':    File "/opt/splunk/etc/apps/Splunk_TA_symantec-ep/bin/splunktalib/httplib2_helper/httplib2_py2/httplib2/__init__.py", line 273, in <module>
12-13-2019 16:13:31.818 +0100 ERROR ScriptRunner - stderr from '/opt/splunk/bin/python /opt/splunk/bin/runScript.py setup':    File "/opt/splunk/etc/apps/Splunk_TA_symantec-ep/bin/splunktalib/rest.py", line 9, in <module>
12-13-2019 16:13:31.818 +0100 ERROR ScriptRunner - stderr from '/opt/splunk/bin/python /opt/splunk/bin/runScript.py setup':    File "/opt/splunk/etc/apps/Splunk_TA_symantec-ep/bin/splunktalib/conf_manager/request.py", line 1, in <module>
12-13-2019 16:13:31.818 +0100 ERROR ScriptRunner - stderr from '/opt/splunk/bin/python /opt/splunk/bin/runScript.py setup':    File "/opt/splunk/etc/apps/Splunk_TA_symantec-ep/bin/splunktalib/conf_manager/conf_endpoints.py", line 3, in <module>    
12-13-2019 16:13:31.818 +0100 ERROR ScriptRunner - stderr from '/opt/splunk/bin/python /opt/splunk/bin/runScript.py setup':    File "/opt/splunk/etc/apps/Splunk_TA_symantec-ep/bin/splunktalib/conf_manager/conf_manager.py", line 10, in <module>
12-13-2019 16:13:31.818 +0100 ERROR ScriptRunner - stderr from '/opt/splunk/bin/python /opt/splunk/bin/runScript.py setup':    File "/opt/splunk/etc/apps/Splunk_TA_symantec-ep/bin/symantec_ep_script.py", line 5, in <module>

This is directly from command line:

splunktest:~ # /opt/splunk/bin/splunk cmd python /opt/splunk/etc/apps/Splunk_TA_symantec-ep/bin/symantec_ep_script.py
Traceback (most recent call last):
  File "/opt/splunk/etc/apps/Splunk_TA_symantec-ep/bin/symantec_ep_script.py", line 5, in <module>
    from splunktalib.conf_manager import conf_manager as conf
  File "/opt/splunk/etc/apps/Splunk_TA_symantec-ep/bin/splunktalib/conf_manager/conf_manager.py", line 10, in <module>
    from splunktalib.conf_manager.conf_endpoints import \
  File "/opt/splunk/etc/apps/Splunk_TA_symantec-ep/bin/splunktalib/conf_manager/conf_endpoints.py", line 3, in <module>
    from splunktalib.conf_manager.request import _content_request
  File "/opt/splunk/etc/apps/Splunk_TA_symantec-ep/bin/splunktalib/conf_manager/request.py", line 1, in <module>
    import splunktalib.rest as rest
  File "/opt/splunk/etc/apps/Splunk_TA_symantec-ep/bin/splunktalib/rest.py", line 9, in <module>
    from httplib2 import (socks, ProxyInfo, Http)
  File "/opt/splunk/etc/apps/Splunk_TA_symantec-ep/bin/splunktalib/httplib2_helper/httplib2_py2/httplib2/__init__.py", line 273, in <module>
    CA_CERTS = certs.where()
  File "/opt/splunk/etc/apps/Splunk_TA_symantec-ep/bin/splunktalib/httplib2_helper/httplib2_py2/httplib2/certs.py", line 35, in where
    return custom_ca_locater_where()
  File "/opt/splunk/etc/apps/Splunk_TA_symantec-ep/bin/splunktalib/ca_certs_locater.py", line 30, in get
    return _get()
  File "/opt/splunk/etc/apps/Splunk_TA_symantec-ep/bin/splunktalib/ca_certs_locater.py", line 50, in _get
    _fallback()
  File "/opt/splunk/etc/apps/Splunk_TA_symantec-ep/bin/splunktalib/ca_certs_locater.py", line 60, in _fallback
    raise ImportError('Unable to load system certificate authority files')
ImportError: Unable to load system certificate authority files

Can someone help out?