Obtaining and installing a valid SSL certificate from a trusted certificate authority A critical step in implementing SSL encryption for Tableau Server is to obtain and install a valid SSL certificate from a trusted certificate authority. This ensures that the communication be-tween the server and clients is encrypted and secure. Using a certificate from a trusted authority al-so helps in avoiding trust issues with clients connecting to the server. Option A is incorrect because a self-signed SSL certificate might not be trusted by all clients and can lead to security warnings. Option C is incorrect as enabling HTTP does not contribute to SSL encryption; instead, HTTPS should be used. Option D is incorrect because disabling firewalls can compromise the overall security of the server and is not necessary for SSL implementation.