Help with a export plugin

Context : SDK 6.0, lightroom classic 6.4, lua plugin

I’m stuck with a LrExportSession:init error : params table must have export setttings
 

    local settings = getExportSettings()

    local exportSession = LrExportSession( {
        photos = photos,
        settings = settings
    } )

I read the post

I did create a template for export 
I read it with dofile()
I check with a dialog that I have parameters I tryed with and with “LR_” .. replacement :
 

-- Main helper function defining all export parameters
local function getExportSettings()

    -- 1. Build the absolute path to the file inside your plugin folder
    local templatePath = LrPathUtils.child(_PLUGIN.path, "export_linux.lrtemplate")

    -- 2. Load the .lrtemplate file
    dofile(templatePath)
    local preset = s.value

    local settings = {}
    for k, v in pairs(preset) do
        settings["LR_" .. k] = v
    end

    -- debug info
    local settingsText = "Export Settings:\n\n"
    for k, v in pairs(settings) do
        if type(v) == 'table' then
            settingsText = settingsText .. k .. " = {\n"
            for subk, subv in pairs(v) do
                settingsText = settingsText .. "  " .. subk .. " = " .. tostring(subv) .. "\n"
            end
            settingsText = settingsText .. "}\n"
        else
            settingsText = settingsText .. k .. " = " .. tostring(v) .. "\n"
        end
    end
    LrDialogs.message( "VERIF", settingsText, "info" )

    return settings
end

But I don’t get export session to start

thanks for any help