Possible errors in the use of the electronic certificate
Skip information indexCertificate selection in Google Chrome
If you use Google Chrome and the browser does not allow you to select a different electronic certificate, follow these instructions:
Close the browser window by clicking on "Customize and control Google Chrome" (three vertical dots icon) at the end of the address bar and then on "Exit".
If you still cannot choose a certificate when you log back in, click on "Settings", "Advanced Settings", "System" and disable the option "Continue running applications in the background when you close Chrome".
Restart the browser and try the procedure again.