Sorry to resurrect this old thread, but I ran across this post in my search to solve my problem and thought I'd share the solution.  Here's the error in the log: /opt/splunk/var/log/splunk/ta_tenable_tenable_securitycenter.log requests.exceptions.SSLError: HTTPSConnectionPool(host='mytenableserver.mycompany.local', port=443): Max retries exceeded with url: /rest/system (Caused by SSLError(SSLCertVerificationError(1, '[SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed: self signed certificate in certificate chain (_ssl.c:1161)'))) There used to be a UI option in the Addon to disable certificate verification, but apparently this functionality was removed by Splunk, so to fix it there are 2 options described below in case the Tenable KB article changes in the future.  Note that any update to the Addon would overwrite these changes, so you'll have to do them each time you update it. Best Option:  Append your custom CA cert to the one in the certifi folder.  Change the script to reference your CA certificate chain file (text file with all the certificates BASE64 encoded). Command to append our CA to the certifi cacert.pem file su splunk cp /opt/splunk/etc/apps/TA-tenable/bin/ta_tenable/certifi/cacert.pem /opt/splunk/etc/apps/TA-tenable/bin/ta_tenable/certifi/cacert.pem.original cat /opt/splunk/etc/auth/mycerts/mycustom-ca-chain.pem >> /opt/splunk/etc/apps/TA-tenable/bin/ta_tenable/certifi/cacert.pem Next option:  Disable SSL certificate verification (less secure). /opt/splunk/etc/apps/TA-tenable/bin/tenable_consts.py verify_ssl_for_sc_api_key = False Source: https://docs.tenable.com/integrations/Splunk/Content/Splunk2/ConfigureTenablescCertificatesS2.htm ... View more