New install - Mesh installed - Files throws error when selected in UI

Hello,  

Managed to get files and chats installed. When selecting files in the UI for a user, the following exception is thrown and appears in a popup.

Json.parse: unexpected character at line 1 column 1 of the JSON data

The open file dialog allows me to select a file and I can see the file in the UI and remove it. However it never uploads and sits at 0% complete.

Has anyone else encountered this?

Thanks