Please follow the below instruction to resolve the above error.
- Please check the "TLS 1.1 and TLS 1.2" is disabled in the Internet explorer settings.
- Go to Internet Explorer an click on the setting.
- Select "Internet Options" and go to "Advance" tab.
- If you are using the old FortiClent versions can getting the above error. Therefor please upgrade to the new version.
- Make sure you have the internet connection. The 80% of this issue getting by not having the internet connection.
- If the above options are not working, please contact your IT Help-desk to check the server issues as a hit the traffic at the moment or a any downtime at the server.