Unable to upload Fortinet Configuration file to Migration Tool, due to Error "no firewall found".
The issue was observed in the Fortinet configuration files containing VDOMs as the migration tool fails to parse the VDOMs settings file.
The workaround for this, i.e. Fortinet, allows you to merge the VDOMs by disabling the Virtual Domain feature, which should allow to download a file that can be processed by the Migration tool.
NOTE: This has been tested and confirmed to be working on Migration tool 4.35.3
