The problem seems to sporadically happen after restoring configuration of an appliance from a backup. The specific error encountered is 'SSL connection cannot be established' when attempting to connect with the Kerio Control VPN client.
The issue seems to be caused by a corrupt/invalid SSL certificate in the VPN server configuration.
The issue can be resolved by correctly attaching the SSL certificate to the VPN server. This can be done by following these steps:
- Navigate to 'Interfaces' in the system settings.
- Select 'VPN Server'.
- Click on 'IPSec VPN server'
- Select the correct certificate from the list
- Click on 'Kerio VPN server' and apply step 4 once more
- Click OK
- If the issue persists, this means that the SSL certificate is corrupted, so proceed to Creating a certificate signed by Local Authority, and go again through the above steps.
- Alternatively, you can Create a certificate signed by a Certification Authority as indicated in the above-linked article
What causes the 'SSL connection cannot be established' error in the VPN client?
This error is often caused by the SSL certificate not being correctly attached to the VPN server or the SSL certificate is corrupt.
How can I resolve this issue?
You can resolve this issue by correctly attaching the SSL certificate to the VPN server through the system settings under 'Interfaces' 'VPN Server' or creating a new SSL certificate.
Will updating the system to the latest version resolve this issue?
No, updating the system to the latest version will not resolve this issue if the SSL certificate is not correctly attached to the VPN server.