Insufficient quota to proceed (503) errors when using GData APIs and Data Feed Query Explorer

[Tom Collier]

Starting over the weekend, all of my app's calls to the GData APIs for Google Analytics results in an "Insufficient quota to proceed" error message. Additionally, when I use the Data Feed Query Explorer to pull down any data, the "Get Data" button appears unresponsive. When I open up the JS console on my browser, though, I see that clicking the button does issue an HTTP request, but the response has a "Insufficient quota to proceed" error message.

In my app, the URL that I use to request data has the parameter "key=<API_key>" (with my actual sever key value of course), but my Google API console (https://code.google.com/apis/console) reports zero usage for that key. For example, my URLs (with sensitive data snipped out) look like:

https://www.google.com/analytics/feeds/data?ids=ga%3A<snip>&metrics=ga%3AuniquePageviews&start-date=2012-01-23&end-date=2012-02-06&max-results=50&key=<snip>

Am I using the API keys incorrectly or is there a bug? It's strange to me that this was working fine until a day or two ago and then just stopped working with no changes to my app.

[Tom Collier]

I generated a new API key and this seems to have resolved the issue.