Excel cant open this file format error

[saroar]

i like to download for each index or show page
here in my code look like

collection_action :download_xlsx, method: :get do
project = Project.find(params[:id])
send_data(filename: "#{project.project_name}.xlsx", type: "application/xlsx")
end

index do
column 'Download Links' do |c|
link_to 'Download', download_xlsx_admin_projects_path(id: c.id, format: :xlsx)
end
end

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