https://experience.dynamics.com/ideas/idea/?ideaid=13c1a9fd-7143-ef...
The error usually occurs when you try to install QuickBooks update or while trying to upgrade it to a newer version and the Windows firewall is still not updated, this causes the firewall to detect QBDBMgrN service as an unknown service, and it blocks its access to the internet.

How to fix qbdbmgrn not running?