It seems the Gmail service went down today. And in response to a request for an explanation about the problem, Google sent the following statement to InternetNews.com:
Since about 2 p.m. Pacific Time today, many Gmail users have
been unable to access their email. We are very sorry for this
interruption in service. The issue is being caused by a temporary
outage in the contacts system used by Gmail, which is preventing Gmail
from loading properly. We are starting to roll out a fix now and hope
to have the problem resolved as quickly as possible. Even though you
may not be able to get to your inbox right now, your mail is safe,
including new incoming messages.
The point: All systems go down at one point or another.