If you are experiencing an error when downloading report data for failed, sent, or complaints it is most likely due to a limitation in the amount of data contained in your report. If you view a report and the number of records returned is larger than 20,000 records you will most likely experience an error when attempting to download the report data. This is because the amount of data and the size of the file make it difficult to handle that much data and the server request simply times out.
So how do you get around this problem? Here are a few suggestions:
Break your report up into smaller increments. You may need to do several downloads on smaller date ranges in order to be able to download the information.
If daily increments are still too large you can use the Email OnDemand API calls to break up the increments into hours. You can call the API directly from your browser and capture data that way.
Here is an example of an API call to get hourly data:
This call would download an hour's worth of data for the given date. To download more data you simply advance the hours on the startDate and endDate parameters.