I just had this same problem with 6.4.0 and found a workaround. The Tenable docs for Add-On describe a setting "Verify SSL Certificate" that for whatever reason is not visible from the UI. https://docs.tenable.com/integrations/Splunk/Content/Splunk2/ConfigureTenablescCertificatesS2.htm Modify /opt/splunk/etc/apps/TA-tenable/bin/tenable_consts.py Change True to False where applicable to your deployment. Save and close the file. No restart required. verify_ssl_for_ot = False verify_ssl_for_sc_cert = False verify_ssl_for_sc_api_key = False verify_ssl_for_sc_creds = False   ... View more