Kerio Control Web Filter Is Not Activated Categorization Is Disabled Hot _hot_ May 2026

Kerio Control uses DNS queries to reach its update and categorization servers. If your ISP or current DNS configuration is slow or blocking these requests, the filter will deactivate.

Avoid using Google DNS (8.8.8.8) for Zvelo categorization as it can cause "Invalid Authorization" errors. Instead, use Cloudflare (1.1.1.1) or OpenDNS (208.67.222.222). Kerio Control uses DNS queries to reach its

Ensure your Kerio Control Web Filter license is active. Without a valid subscription, the module defaults to a trial state and eventually disables itself. Instead, use Cloudflare (1

Kerio deactivates the filter if 10 consecutive DNS queries fail within one minute. Usually, it tries to re-enable itself after one hour, but a manual restart is often faster. 2. Resolve "Invalid Authorization" Failures Kerio deactivates the filter if 10 consecutive DNS

The error typically occurs when the firewall cannot reach the Zvelo categorization servers or when the license token has expired. This is often triggered by DNS failures, where the system marks the filter as "unreliable" after multiple failed connection attempts. Core Troubleshooting Steps 1. Verify DNS and Reachability

If your error log specifically mentions "Invalid Authorization," it likely means the has expired (tokens typically last 21 days).