When your browser prompts you for an electronic certificate, if the selection window is blank and there is no certificate listed, you need to check that your electronic certificate has been installed correctly.
If your certificate is not installed or is not installed correctly
Go to "Tools", "Internet options" and select the "Contents" tab.Click on the "Certificates" button and check the expiry date of your certificate.You can also go to the issuing entity's website to check if the certificate has expired or has been revoked.The certificate must appear on the "Personal" tab for the installation to be valid.
If the certificate was imported from an invalid copy, it will appear in the "Other people" tab instead of in the "Personal" tab and it will not be valid for accessing the procedures on the Tax Agency website.If this is the case, check if you have a valid copy of your certificate.The icon for a valid copy is an open envelope with a green certificate sticking out and a key, with the file extension.pfx or.p12.
If the copy is invalid (the icon is a green certificate with no key;and the file extension is.cer) this is because when exporting it you did not tick the box "Export the private key", which is the personal information contained in the certificate and without which it is not enabled for signing.If you do not have a valid copy that allows you to correctly import the certificate (to the "Personal" tab), you will have to request a new certificate by repeating the entire process.
In the "Useful links" section, it may be helpful to consult the help topic on importing certificates.
If your certificate is correctly installed
To be able to carry out the following actions, we recommend that you run Internet Explorer in Admin mode.To do this, right click on the Internet Explorer icon and then "Run in Admin mode" to open a window.
Go to "Tools" in the menu on the top of the browser window (top right hand corner) and then "Internet Options".On the "Security" tab, press "Reset all zones to default";tick "Trusted sites", then go to "Sites" and add the following URL:https://*.agenciatributaria.gob.es/".The box "Require server check (https:) for all sites in this area" must be ticked.
In the "Privacy" tab, untick the box "Enable pop-up blocker".In the "Advanced options" tab, click on "Restore advanced configuration".
Then, go to the "Contents" tab and click on "Certificates".Select your certificate in the "Personal" tab and press on the "View" button.
Inside the "Details" tab, go to "Edit properties" and tick the option "Enable all purposes for this certificate".If you have more than one certificate installed on the computer, you can assign a name to each certificate in the field in order to make it recognisable when selecting it.
Accept the windows for the changes to be saved and, back on the "Certificates" window, enter the "Entities with trusted root certificates" tab, as these actions must also be done for the issuing entity's root certificate.Select the root certificate of your issuing entity and double click on it (e.g. if it is the FNMT you should select the certificate "FNMT Class 2 CA" or "AC FNMT Users" if your certificate was issued after 1 March 2015).
Inside the "Details" tab, go to "Edit properties" and tick the option "Enable all purposes for this certificate".Then click "OK".To finish, click on "Apply" and "OK".In order for the change to take effect, you will need to close all Internet Explorer windows you have open and restart.
If your operating system is Windows Vista or earlier, the option you should use inside the "Details" tab to tick the option "Enable all purposes for this certificate" is "Modify properties".