If you are a big Google AdWords API user and you have been messing around in the API's Sandbox yesterday or today, you may have been experiencing some issues. Many API users are reporting weird glitches with the sandbox.
Errors are being returned to API users after API calls. The errors are all over the place, but you can see a few mentioned in the Google Groups thread.
Jeff Posnick of the AdWords API Team confirmed the issue, saying:
I can answer the "SandBox wigging out?" question in the affirmative: yes, the Sandbox is wigging out. It's having some trouble coming back after one of its periodic data refreshes. The engineering team is aware of the issue and is working on normalizing things.
Typically, AdWords API Sandbox issues are not a priority for Google's engineering staff. Why? Well, the sandbox is for testing purposes only. So it is not a live production issue that impacts real users, with real dollars. It is a sandbox, playground, if you will. So hopefully this will be taken care of shortly, we will see.
Forum discussion at Google Groups.