Obtain Error on API in excel

I use the API in an excel spreadsheet and has been working fine but today started getting the following error:
Unexpected error: The given key was not present in the dictionary.
Details: Microsoft.Mashup.Evaluator.Interface.ErrorException: The given key was not present in the dictionary. —> System.Collections

Hello, we can’t offer help with Excel, but if you post your api query (with key removed) we can check to ensure our API is functioning properly and answer any questions about the request or response.

Nick :

Thanks for responding, but it wasn’t the query as it has been working for about a year and suddenly it stopped working yesterday. I got a new key this morning through your web site and it works so I know it was the key. FYI, the old non functioning key is:

2a6e…b087

Hello,

That key appears to be working fine. We don’t shut down keys after any period of time or at random without notice. It’s possible you were hitting rate limits, in which case the new key would be affected as well.

I’ve censored the key in your post so that you can continue to use it if you wish.

Nick :

What are the rate limits for the free account?

One request per second, evaluated each second.