unknown or unclassified error
invalid arguments
the connection was invalid
attempted to set an invalid hostname
the requested operation is not supported by any active settings backend
permission denied
attempted to modify a read-only connection
a connection with that UUID already exists
Errors related to the settings/persistent configuration interface of NetworkManager.
These may be returned from #NMClient methods that invoke D-Bus operations on the "org.freedesktop.NetworkManager.Settings" interface, and correspond to D-Bus errors in that namespace.