I try to mass download PDF invoices by accessing the following url for each order on new tabs but when trying to open more than 5~6 at the same time, I always get the error above and can't download some invoices.
https://**********.com/admin/pdfgenerator/order_invoice/printpdf/template_id/1/order_id/67529/invoice_id/124120/
Am I requesting too much at the same time? I would like to download at least 50 at the same time. Is there a way to enable it on Magento 2?