When I try to edit it gives me this message: We apologize for the inconvenience, but we are unable to process your request at this time. Our engineers have been notified of this problem and will work to resolve it. I wonder if it's prevalent throughout all AdSense accounts.
Didn't have any issues today but the Google interface is known to be buggy at times. I've had plenty of issues with AdWords giving random errors, especially with the editor.
It's has been going on for 4-5 hours now. It's kind of annoying since I wanted to remove the border from one of my ads. Oh, well, we shall wait...... Added later: Seems like quite a few folks are having this issue: https://productforums.google.com/forum/#!category-topic/adsense/working-with-my-ads/fDFb2nXX72g