Troubleshooting Tip: A valid upgrade path cannot be determined for manually uploaded firmware

[hlngan]

Description	This article describes the error message 'A valid upgrade path cannot be determined for manually uploaded firmware' even when the upgrade path and image are valid.
Scope	FortiGate.
Solution	This is because FortiGate will access the FortiGuard server to check the valid upgrade path. If the FortiGate does not have internet access: When upgrading with a manually uploaded image to the FortiGate, a message will be shown: Example from v7.2.x: Example from v7.4.x: If the correct upgrade path is followed and the image is valid, the message can be ignored and the upgrade can proceed. Check the upgrade path using the Upgrade Path Tool or the Fortinet Support Portal. Refer to Technical Tip: How to verify FortiGate Upgrade path to upgrade the FortiGate to a higher Firmware Ve... for more details. The same message shown in the above snapshot is also displayed if the FortiGate cannot resolve the FQDN due to a DNS issue/reachability.  Further steps to troubleshoot and update the FortiGate's list of firmware images and paths can be seen in this KB article: Troubleshooting Tip: No firmware available from FortiGuard under firmware management