How do firewall or antivirus programs interfere with Steam and cause error code 50, and how can this be addressed?

Firewall or antivirus software can sometimes aggressively block Steam's access to the internet, preventing it from loading web content. To address this, check your security software's settings to ensure 'Steam.exe' and any related Steam processes are added to its exception list or allowed applications. As a diagnostic step, you can briefly disable your firewall/antivirus (with caution) to see if the error resolves, then re-enable it and configure proper exceptions.