Below error is displayed while opening the office document in edit mode.
"We have trouble connecting to the server. If this keeps happening, contact your help desk"
IIS logs or Fiddler logs from the SharePoint Web Front End Server show a failure http code '404' (Not Found) for the cellstorageservice call.
POST /_vti_bin/cellstorage.https.svc/cellstorageservice - 82 0#.w|TestDomain\user1 111.11.111.1 Microsoft+Office+Word+2014+(16.0.9126)+Windows+NT+6.3 - 404 0 0 31
The 'cellstorageservice' service is used by the SharePoint/Office co-authoring feature. This feature (co-authoring) is currently not compatible with the EnterpriseVault-SharePoint-HttpModule, as EV uses the WebDav protocol in accordance with an earlier recommendation made by Microsoft. However with on-going design changes in the Office apps, they have recently suggested moving to FSSHTTP-SOAP protocol in order to support co-authoring.
Workarounds:
1. Disable the CellStorage service.
Below SharePoint powershell commands can be used.
1. $webapp = Get-SPWebApplication https://....WebApplicationUrl..
2. $webapp.CellStorageWebServiceEnabled = $false
3. $webapp.Update()
Note: Co-authoring will not be available with CellStorage disabled.
2. Configure Office Online Server and open the item using this method.
3. Download the item from SharePoint.