Users frequently get QuickBooks Error 12009 when upgrading QuickBooks or downloading payroll updates. Typically, firewall configurations, Internet security settings, or issues with network connections are to blame. To resolve this error, users can check their internet connection, disable the firewall temporarily, and configure the Internet security settings.
Additionally, update QuickBooks to the latest version and ensuring the system is up to date can also help resolve Error 12009 and ensure smooth functionality. Dial +1-(855)-955-1942 and talk to QB experts.

Read: https://dohaj.com/blog/ways-to-troubleshoot-quickbooks-error-12009/