error handling could be improved

[karenetheridge]

There is no visual difference between an api call never returning, and the api returning an unexpected error (whether that's an http 500 (api exploded) or 4xx (auth error, input validation error, data conflict etc)). Could there be more code added to the Promise.reject(..) path to differentiate between different error conditions? A modal popup indicating the error condition in on staging servers would be helpful, or a sad panda emoji otherwise, or something other than an infinite spinner which the operator interprets as "keep waiting, this is taking a long time".