While working with a client yesterday we noticed users could not view Excel files in browser. A quick analysis of ULS logs revealed the following issue:
There was an error in communicating with Excel Calculation Services http://server_name:port/2a7905259ea644f3a2d8ebd2bcf1ee9f/ExcelService*.asmx exception: An error has occurred. ServerSession.GetNextServerHealthBased: There are no healthy servers although the number of available server in the farm is {1}; updated with no candidates available for the health based load balancing. The update duration was {0} millisecs.
Here is what you can do to fix this issue:
- Use PowerShell command Get-SPSessionStateService to check the state of Session State Service Application (it has to be Enabled)
- Using Enable-SPSessionStateService command to enable the service
- Restart IIS
Hope this help!