While connecting the Kerio Control appliance to 2 different providers (ISP), the Kerio VPN client connection is not reachable. One of the Internet link connection (PPPoE) cannot reach the Web interface.
This article provides information on how to resolve such issues.
PPPoE connections usually require a certain MTU size value to be specified. Incorrect or default settings may lead to VPN client-server communication problems.
In Kerio Control Webadmin > Interfaces, modify the PPPoE interface advanced settings and enter the correct MTU.
Important: check the correct MTU value with your ISP.
Try to access the Web interface using both ISP links. The connection should be established successfully by using each of them.