This works for me - I have not /etc/at.allow file and running the command from the description did something.
$ at teatime tomorrow warning: commands will be executed using /bin/sh at> <EOT> job 1 at Tue May 24 16:00:00 2016 ** Package changed: ubuntu => at (Ubuntu) ** Tags added: xenial -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1584501 Title: at (at-3.1.18-2ubuntu1) doesn't seem to be working correctly To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/at/+bug/1584501/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs