Just like the Firewall settings, this antivirus software could be blocking Roblox on your device. A quick fix for such issues is disabling the antivirus while using Roblox.

If Roblox Marketplace is not working or loading and you see If you are having trouble loading Marketplace message, then see this post.

If Roblox chat is not working or showing up on Windows 11/10, then try to change keyboard language, adjust Roblox privacy settings, etc.