Display error messages from backend

[enriquezrene]

Backend is providing detailed messages when bad data is provided so we need to display them in the UI.

Acceptance Criteria

• Make sure no technical data is being provided by the back-end (Talk to Roberto Mena)
• Display error messages from the backend in the UI
• Display a generic error message only if the server is down or some technical part is not working (like no connection to the db or so)