I am unable to open one web page which I used tobe able to open, error message unable to open.

[WPCentral Question]

I have a surface RT. I have been logging into my online banking without a problem, suddenly now the address is not being recognised and I cannot access. I have tried rebooting, resetting, and recovery. If I log in when I am using my works intranet I can then log into the account I can also access using my phone. so I know there is nothing wrong with the address. I have contacted Microsoft who don't seem to be able to help.