This article describes how to troubleshoot External Connector-Threat Feeds support format.
When the threat feeds are imported from a remote HTTP server, there is no entry on FortiGate.
The data is visible by HTTP access.
Open the threat feed file by notepad++ then browse to the option Encoding the current format will be visible.
The format can be modified using the tool Convert to UTF-8.
The threat feed data can be imported correctly.