This is the resume of my issue:
1) Drupal has a module named RESTful Web Services
2) The CouchDB module use this module (RESTful Web Services) to receive the sync requests
3) The sync request are made using common http requests types (PUT,GET,DELETE,etc)
4) When a document is deleted in the LocalDB (PouchDB), the sync process try to delete it in
the server sending a DELETE request but this request its rejected.
5) So, DELETE requests are being rejected by the RESTful Web Services module.
6) The official documentation says that this module need to be reconfigured to receive DELETE requests.
Where i can find more details about this modification?