Over the weekend and on Friday, many Google AdWords users began complaining they could not login to their AdWords account.
Google posted a thread at the Google AdWords Help forum that this is a known issue. In fact, AdWords representative Bindu posted a work around saying you can go to https://adwords.google.com/cm/CampaignMgmt to access your account. Bindu said:
However, this morning or earlier, Google seemed to have resolved the issue.
Google moved this known issue to the “recently fixed” box.
Forum discussion at Google AdWords Help.