Problem : If you encounter a blank page while opening Adwords page and see adwords (1×1) in the page tile like the screenshot shown below.
I alerted @google and @adwords to find a solution to this problem. But this could not be replicated by them. Despite clearing cookies and history and trying to open adwords in different browsers in regular and incognito windows the problem persisted.
Cause : This happens when your antivirus / firewall program blocks Google.com/adwords or adwords.google.com website.
Solution: Open your antivirus program and allow the urls
Google.com/adwords and adwords.google.com
Refresh the page multiple times and you will see the login page.
This process depends on what antivirus software you are using. e.g I have Kaspersky and this is how it looks.