This Friday, dozens of reports came from the Google AdSense Help forum that Google AdSense ads were simply not loading.
The reports continued throughout the day and publishers were not making money, at all.
The reports were sporadic, not all publishers saw their ads as being offline, only some.
Google confirmed the issue at Marketing Land and in the Google AdSense Help forums. Chris from Google said:
Thanks for posting about this here. I'm working to get you more info on what happened, but in looking at many sites it does appear that ad serving has been restored.I'll try to post here as soon as possible, as well as updating the Known Issues page.
Thanks for your patience.
Then later on in the day, he said it was fixed:
I just got confirmation from our engineering teams that ad serving is back to normal for all partners at this point. Thanks for your patience and attention here!
But even after that post, some publishers said there was still an issue. But now, a few days later, it seems everyone now is serving up ads properly. It is however still listed on the known issues page as an issue.
One publisher asked a legit question:
Our ads are back too and working fine but we've lost income. It means that our lost on that day is not recoverable?
Yep, if no one saw the ads - I doubt you'll be getting paid for it.
Forum discussion at Google AdSense Help.