Issues obtaining an electronic copy or full enquiry
Skip information indexProblems obtaining an electronic copy Firefox - Windows
Check your browser to make sure the "Block pop-up windows" option is unchecked. To do this, access "Tools" or the icon with three horizontal stripes located at the top of the right margin, "Options" ("Firefox", "Preferences" on Macintosh; "Editing", "Preferences" in Linux) check "Privacy and Security" and locate "Permissions". If you want to only allow pop-up elements from the AEAT website, click on "Exceptions" and add the following address: https://*.agenciatributaria.gob.es. Press "Allow" and "Save changes."
Also the existence of a firewall, antivirus, or even a proxy, can affect the operation of declaration consultations and generation of PDF files on the Tax Agency's website.
Check that the browser configuration is correct to work on the AEAT website:
So that the changes can be applied, accept all windows and restart the browser by closing all pages and tabs open from the "Exit Firefox" option (do not close the browser window with the cross as the processes would still be active).
As for the rest of the requirements to be able to correctly carry out a complete query, remember that it is necessary to have a PDF document viewer.