FortiClient IPsec disconnect

I am having an issue with FortiClient (IPsec). Even if my internet connection drops for just a second, FortiClient disconnects. How can I fix this? I am using the free version of FortiClient, and I would like to know if there is a way to adjust this behavior, either on FortiGate or within the FortiClient settings. Is there a possibility to adjust this setting, for example, by modifying the configuration file after performing a backup?