There was a problem.

There are cookies on your computer that are keeping you from logging in, but we can fix this.

So how do I fix this?

You have two ways, the easy way and the hard way.

The easy way.

1. Press Ctrl + H
2. Next press the button "Clear browsing data..."
3. Then you will see a dropdown select that says "The past hour", change this to "From the beginning of time"
4. Uncheck all but the checkboxs that say "Cookies and other site and plugin data" (3rd down) and "Hosted app data" (7th down)
5. Finally press the button that says "Clear browsing data"
6. Now completely close out the browser then go back to gmail login

Now if you would like to do things in a bit more complicated way.

The hard way.

1. In Chrome.
2. In the top right, click the Menu.
3. Click Settings > Show advanced settings.
4. In the "Privacy" section, click Content settings.
5. Under "Cookies," click All cookies and site data.
6. Scrol until you see google.com, accounts.google.com, mail.google.com and gmail.google.com click the on the right next to each of these
7. Now completely close out the browser then go back to gmail login