I should add to my comment(#8), above, that the _sending_ machine is running 18.04 LTS desktop, the _receiving_ machine is running 16.04.4 LTS server and deja-dup is backing-up over an ssh connection.
I should add to my comment(#8), above, that the _sending_ machine is running 18.04 LTS desktop, the _receiving_ machine is running 16.04.4 LTS server and deja-dup is backing-up over an ssh connection.