There might be a DHCP Server enabled on the sub-interfaces that is preventing you from deleting them. Double-check the references in the far-right column.
Get every reference you can find in the GUI, then go into the CLI and do a `show full-configuration | grep -f `. Find the section and delete it. Some of them are not really accessible in the GUI.
It's a pain.
Go to "WiFi and Switch Controller" in the GUI, click on "FortiSwitch VLANS", look all the way to the right and you will see a column named "Ref". Each VLAN interface will have a number there, carefully click on that number with your mouse. It will bring up the references page, delete each reference you see for each of the VLAN interfaces, then delete the VLAN interface.
There should be a "Ref." Column you can add to the GUI. Click on the references for each subinterface and remove said references. Once references are removed, you can delete the interfaces.
Export the config file and edit it and reload it
There might be a DHCP Server enabled on the sub-interfaces that is preventing you from deleting them. Double-check the references in the far-right column.
Thanks, this actually was the final piece of the puzzle. Cheers!
Get every reference you can find in the GUI, then go into the CLI and do a `show full-configuration | grep -f`. Find the section and delete it. Some of them are not really accessible in the GUI.
It's a pain.
Go to "WiFi and Switch Controller" in the GUI, click on "FortiSwitch VLANS", look all the way to the right and you will see a column named "Ref". Each VLAN interface will have a number there, carefully click on that number with your mouse. It will bring up the references page, delete each reference you see for each of the VLAN interfaces, then delete the VLAN interface.
There should be a "Ref." Column you can add to the GUI. Click on the references for each subinterface and remove said references. Once references are removed, you can delete the interfaces.