Do you see this message in your adsense account?
There was indeed some planned system maintenance occurring at the time you wrote, dantoI. Sorry if it caught you off guard.
When maintenance is planned, we try to give advance notice with a small message at the top of your Campaign Summary page, as did occur in this case.
Also, I usually will post to this Forum with an alert, which, I now realize, I failed to do this time. And finally, such alerts are also routinely posted on the AdWords blog, a day or two in advance of the actual maintenance.
AWA