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:
We are aware that there are some accounts affected by a technical issue which is preventing them from accessing their AdWords account. Please be assured that our Engineering team are working to resolve this as a high priority and we hope to have it fixed very soon.
In the meantime, as a workaround we recommend logging into your account via https://adwords.google.com/cm/CampaignMgmt as this will avoid the issue.
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.