Today OVH disabled Keystone (OpenStack Identity Service) API v2.0 and requires all endpoints to now use v3.
As the OVH instructions to access Swift via CyberDuck with Keystone v3 were incorrect, I have made a post with the correct settings: https://www.hugogameiro.com/cyberduck-with-ovh-swift-v3/
Also, made one for Transmit: https://www.hugogameiro.com/transmit-with-ovh-openstack-swift-v3/