OK I think I know what went wrong here, not the technical terms but practical ones. If you look at the screen shot you submitted, the date under the World selection you will see it is different than the date at the top. I had the same problem as you and was unable to log on to my account for about 4-5 days.
A security certificate error means that the date on your computer is not the same as the game hence the game is unable to log in. If you set the date on the computer temporarily to the date listed by the "All servers are up and running" it should work or at least it did for mine.
Note: You don't have to change time just day and month.
WARNING: IF YOU PERFORM THIS ACTION YOU MUST SET THE DATE BACK TO THE PRESENT AFTER YOU LOG OFF, OTHERWISE YOU WON'T BE ABLE TO SURF THE WEB. THIS IS BECAUSE THE SECURITY CERTIFICATES FOR THOSE SITES WON'T WORK.