Catch NewConnectionError

[giosava94]

Catch the following error, at the lower level:
Failure: Unable to establish connection to https://ibisco-endpoint.na.infn.it:42109/v2.0/networks: HTTPSConnectionPool(host='ibisco-endpoint.na.infn.it', port=42109): Max retries exceeded with url: /v2.0/networks?status=active (Caused by NewConnectionError('<urllib3.connection.HTTPSConnection object at 0x7f4b004dad50>: Failed to establish a new connection: [Errno 111] Connection refused')). Retrying in 0.5s.1 retries left