I started seeing this error in my ULS logs, and the Event Viewer on the server was packed full of red x’s. Fount this TechNet article that talked about this specific error – http://technet.microsoft.com/en-us/library/ee513104.aspx. My error text mentioned a service account that hasn’t has any problems otherwise, but for whatever reason it cant communicate with the Excel Services app. The “solution” to fix it proposed by Microsoft was to restart the server. Now, during my IT support days we would use this to fix 99% of those “my computer is broken” type tickets. I just didn’t think dropping the entire app server during the day would make my users very happy, so I kept looking.
I ran across this article from Eric Harlan about how to look through IIS to find out which Web Application is controlling your Service Applications. Using his process, I figured out which app pool contained my Excel Services service app. In our environment it contains all of our Office service applications (Excel, Word, PP, Visio, Access). I recycled this specific Application Pool and my Event View is no longer a sea of red. It’s been a few days now since I recycled it and I haven’t seen the error come back, so I’ll chalk this one up as complete