Overview

Kerio Control license activation or renewal fails during the registration wizard with two specific errors:

• Unauthorized — shown while sending registration data
• Cannot write new license file — shown during online activation or license-file import

These errors appear together even when the license key is valid. They indicate one of two underlying problems:

1. Blocked HTTPS connectivity — the appliance cannot reach the GFI licensing service over TCP/443 (caused by DNS misconfiguration, firewall egress rules, SSL inspection, proxy requirements, or incorrect system time).
2. Storage write failure — the appliance cannot reliably write the license file to disk (caused by a failing disk, read-only filesystem, or unstable storage hardware such as a failing mSATA drive on NG100 appliances).

Solution

Step 1: Confirm the license key is valid

Check your subscription certificate or the GFI licensing portal to confirm the license key is active and covers the current date. If the key is valid and the errors still appear, continue to Step 2.

Step 2: Check connectivity and system time

1. Reboot the appliance.
2. After reboot, open the Kerio Control dashboard and verify the system date and time are correct. Incorrect time breaks HTTPS/TLS certificate validation.
3. Confirm the appliance can reach the internet:
   • DNS resolution is working.
   • Outbound TCP/443 (HTTPS) is allowed and not blocked by a firewall or proxy.
   • SSL/TLS inspection is not intercepting outbound HTTPS traffic from the appliance.
4. Go to Configuration → Licensing and retry activation.

Step 3: Diagnose and fix storage

The Cannot write new license file error means the appliance cannot write to its local disk. Common signs of a storage problem:

• The disk is intermittently detected by BIOS/firmware (detected on some boots but not others).
• The error appears both during online registration and during license-file import.

Fix: 

• Follow the steps for Diagnosing Faulty hardware boxes
• Use the Diagnostic tool for Kerio Control Box NG series to gather the diagnostic file and identify if there are storage failures.
• In case of storage failure, replace or repair the failing storage. Activation — whether online or offline — will continue to fail until the appliance can write reliably to disk.
  • Depending on your appliance, you may be entitled for an RMA, in which case you can proceed with Requesting RMA for hardware box 

Step 4: Retry activation on stable storage

1. Install Kerio Control on the repaired or replacement drive.
2. Restore your configuration from backup (e.g., from GFI Salvado) if needed.
3. Go to Configuration → Licensing and activate using the license key.

Summary

• Unauthorized + Cannot write new license file together point to a storage write failure, not a licensing or connectivity issue.
• Unauthorized alone (without the write error) can indicate blocked HTTPS to the licensing service — check DNS, TCP/443, SSL inspection, and system time.
• Both online and offline activation require the appliance to write to local disk. Fix the storage before retrying either method.
• If a different error appears after storage is stable (e.g., License is not for this hardware/operating system), see the article for License is not for this hardware or "License is not for this operating system" error on NG boxes for license mismatch troubleshooting.

FAQ

Q1: My license is valid — why do I still get "Unauthorized"?

When Cannot write new license file also appears, Unauthorized is a secondary symptom: the registration process fails because the appliance cannot write the result to disk, not because the license itself is rejected. Fix the storage issue and the error will resolve.

Q2: Can I activate Kerio Control without an internet connection?

Yes. The registration wizard includes a Register by license file option. Download the license.key file from the GFI portal and import it. Note that the appliance still writes the file to local storage during import, so this will also fail if the disk is unstable.