I have a very simple workflow that works as follows: when a person submits a form the submitter is sent an email confirming the information they submitted. This workflow stopped working on April 28. On April 27 my SharePoint 2010 application pool stopped and I had to restart it (not sure if this is connected or not). There are not workflow errors, I've checked the settings and saved and republished the workflow but nothing works. I have a feeling it is something to do in Central Admin but I don't know where to start.

Any help would be appreciated.

Andrew