If you block cookies, you will not be able to log in.
What are cookies? Cookies are small files that websites put on your PC to store info about your preferences. Cookies can improve your browsing experience by allowing sites to remember your preferences or by letting you avoid signing in each time you visit certain sites.
To delete cookies in Chrome
At the top-right, click More - More and then settings.
At the bottom, click Advanced.
Under 'Privacy and security', click Content settings.
Click Cookies and then See all cookies and site data and then Remove all.
Confirm by clicking Clear all.
To delete cookies in Internet Explorer
Select the Tools button, point to Safety, and then select Delete browsing history.
Select the Cookies and website data check box, and then select Delete.