Using Google Chrome.
Gibson Research Corporation Cookie Forensics states to disable 3rd party cookies.
After disabling 3rd party cookies, entering credentials into accounts.google.com reloads the page allowing for the credentials to be entered again. Odd, but after this second time, the page loads correctly.
Attempts to correct #1
ACTION
In Settings, Show advanced settings..., Content Settings (under Privacy), Manage Exceptions (under Cookies); Add the following:
Hostname pattern: [*.]accounts.google.com
Behavior: Allow
RESULT
The address bar began a noticeable loop, finally ending with a message stating "This webpage has a redirect loop."
Attempts to correct #2
ACTION
In Settings, Show advanced settings..., Content Settings (under Privacy), Manage Exceptions (under Cookies); Modify the following:
Hostname pattern (Existing): [*.]accounts.google.com
Hostname pattern (Change to): [*.]google.com
Behavior: Allow
RESULT
The web page loaded successfully with only one login attempt.
CONCLUSION
When 3rd party cookies are disabled, websites may fail to load. In the case of Google, 3rd party cookies are used (and my guess, heavily) throughout their sites. Because of this, when 3rd party cookies are disable, their pages do not load. Initially, the issue appears to be with just the accounts.google.com site. When the accounts.google.com sites are allowed and the page starts looping, it happens so fast that the other google.com sites are unknown. Adding all google.com sites resolves the issue.
MORE INFORMATION
After making these changes, the page will load but additional blocking may show in the address bar. This could be due to Google's acquisition of YouTube. To correct for this, add the following:
Hostname pattern: [*.]youtube.com
Behavior: Allow
