Technical Tip: 'Certificate error -160' on FortiGate firmware upgrade

[ychia]

Description	This article describes why FortiGate displays 'Failed command (error -160)' during an upgrade:
Scope	FortiGate.
Solution	The certificate error can be ignored in the later version as it has changed to 'set source <factory | user | bundle>'.  FortiGuard is no longer used. The source value is only indicating the source that generated this certificate.