ICMP connectivity and DNS resolution look good. I notice that FortiGate cannot establish TLS session with ForiGuard:
upd_comm_connect_fds-Failed SSL connect
Is there is any device between FortiGate and FortiGuard which does deep inspection? Moreover, I would recommend to sniff the traffic towards FortiGuard "diagnose sniffer packet any 'host 220.127.116.11' 6 0 a" and convert it to pcap file.
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