There is security software like Avast, Kaspersky, BitDefender and ESET that intercept secure connections and send their own certificate.

https://support.mozilla.org/en-US/kb/firefox-cant-load-websites-other-browsers-can

https://support.mozilla.org/en-US/kb/firefox-and-other-browsers-cant-load-websites

https://support.mozilla.org/en-US/kb/secure-connection-failed-error-message

https://support.mozilla.org/en-US/kb/connection-untrusted-error-message

http://kb.mozillazine.org/Error_loading_websites

https://www.bing.com/search?q=web+site+access+denied

Hello, Thank you for your prompt reply. Unfortunately it did not help. I tested it on our Xenapps, local windows and macbooks. Each with and without virus protection. It did not make a difference. Proxy, cache has also made no difference. I also tested it with different versions of Firefox (50, 53, 55.58) that makes no difference

Patrick

I accessed your link. And after several re-directs ended up here; http://www.santander.com.mx/mx/home/

Any better?

This Link: https://enlace.santander-serfin.com/eai/EaiEmpresasWAR/inicio.do

Navigate http://www.santander.com.mx/bei/home/ and then on the right side on "Accesso"

Patrick

I had to disable my ad-blocker. Then I got this;

Forbidden You don't have permission to access /EaiEmpresasWAR/inicio.do on this server.

You should contact its support for more help. It may be blocked outside some border.

Please see :

http://www.zonavirus.com/noticias/2017/phishing-del-banco-de-santander-que-intenta-capturar-datos.asp

And :

Google's translation

hello, thank you for the quick assistance.

Patrick