Figured it out. Got it to working. There is a config file inside the apps folder under the add-on, where the proxy settings has to be explicitly mentioned. Under: /opt/splunk/etc/apps/Splunk_TA_microsoft-cloudservices/local/splunk_ta_ms_o365_client_settings.conf [proxy] proxy_enabled = 1 proxy_rdns = 1 proxy_type = http proxy_password = password of proxy account proxy_port = 8000 proxy_url = proxy1.your.server.com disabled = 0 proxy_username = user name of proxy account ... View more