Kerio Control Web Filter Is Not Activated Categorization Is Disabled Hot [top] Jun 2026

What of Kerio Control is your appliance currently running?

Using generic public DNS servers directly can occasionally break the token handshake required by the filter. Configuring a dedicated custom DNS forwarding rule for the Zvelo domain bypasses this problem. Log into your panel. Navigate to Configuration > DNS .

Kerio Control needs proper DNS resolution to contact the GFI/Kerio activation servers. Go to .

What of Kerio Control are you running?

(if option exists in your version) Go to Configuration → Web Filter → Update → Clear Cache or Reset Database .

To help narrow down the solution, could you provide a bit more context?

Fixing the "Kerio Control Web Filter is Not Activated, Categorization is Disabled" Error What of Kerio Control is your appliance currently running

Before diving into technical configurations, check the administrative console.

Web Filter categorization disabled. Serial number: ko-197974

| Cause | Description | |-------|-------------| | | Kerio Control Web Filter requires a valid license (subscription). If expired, categorization is disabled. | | No internet access from Kerio Control | The filter needs to contact Kerio’s cloud categorization servers. Without WAN/DNS access, it fails. | | Web filter service not running | The kerio.webfilter service may be stopped or crashed. | | Misconfiguration in admin interface | Web filter is manually disabled under Configuration → Web Filter → Status . | | DNS resolution failure | Categorization engine cannot resolve categories.kerio.com or related update servers. | | Proxy / upstream firewall blocking | Outbound HTTPS traffic to Kerio’s licensing/categorization APIs is blocked. | | Corrupted local categorization database | Database files may be corrupt, causing the service to disable itself. | | Time/date sync issue | Incorrect system time can break license validation and SSL handshakes with Kerio’s servers. | Log into your panel

Since Web Filter relies on categorizing URLs by domain, proper DNS resolution is paramount.

Also test the license validation server:

After installing a new license, restart the Kerio Control Filtering Service via Status → Services . causing the service to disable itself.

Note: The base firewall license might be active, but the Web Filter requires its own valid software maintenance sub-license. 2. Verify Port 443 and Server Connectivity