Issue: Even after successfully connecting with the ApolloXXXX_TimeMachine volume, when Time Machine attempts to perform a back-up, it fails with an error indicating that the username or password used to connect to the volume is incorrect.
Work-around: Launch the Keychain Access application (found in the Utilities folder under the Applications folder). In the search-bar at the upper-right of the Keychain Access window, type in: “smb”. In the filtered list of SMB passwords that result, find those that contain the name of your ApolloXXXX device. In each (there may be more than one), make sure that the “Account” field matches your Apollo Cloud account username (typically your email address). If it doesn’t, edit that field to make it match.