Checking the Windows server's firewall settings to ensure the necessary ports for Tableau Server are open When Tableau Server on a Windows system is not accessible from client machines, the first troubleshooting step should be to check the server's firewall settings. Ensuring that the necessary ports for Tableau Server are open is crucial for network accessibility. Firewall set-tings that block these ports can prevent client machines from accessing the server. Option A is incor-rect because reinstalling network drivers, while it can solve some connectivity issues, is not the first step to check for server accessibility problems. Option C is incorrect as upgrading client machines' operating systems does not directly address server accessibility issues. Option D is incorrect because setting a static IP address for the server, while helpful for network management, is not the primary concern in addressing accessibility issues.