Error Message

"Something went wrong and we couldn't start this app" is displayed in place of the Application. 

  A Network Trace using Internet Explorers Developer Tools will show the following request. 
/owa/service.svc?action=ExecuteEwsProxy

The response received is as below.

{"Body":null,"ErrorMessage":"Failed to make a request via HttpWebRequest. Exception: Unable to connect to the remote server","StatusCode":0,"StatusDescription":null,"WasProxySuccessful":false}

The URL used for Exchange Web Services is resolvable via DNS but resolves to an incorrect destination.  This results in Exchange.asmx not being able to be contacted for use with Exchange Web Services.

Review the URL's for Exchange Web Services. These can be found using the following Cmdlet via the Exchange Management Shell.

Get-WebServicesVirtualDirectory | Format-List -property Server, Name, ExternalUrl, InternalUrl

Depending on the configuration this may return an Internal URL and External for Exchange Web Services.  For Example.

ExternalUrl : https://owa.domain.com/ews/exchange.asmx
InternalUrl : https://mail.internal.local/EWS/Exchange.asmx

You should be able to browse to both of these though you may receive a blank page a 200 success code is returned.   Both of the above should resolve/contact the Client Access Servers.  If this is not the case review your environment and configuration.

On a new Deployment using the Enterprise Vault Office Mail App via Outlook Web Access, the Enterprise Vault Office Mail App fails to load.