Can't upgrade Ubuntu Gnome 16.04.3 to 17.04

I cannot upgrade Ubuntu Gnome 16.04.3 to 17.04. I have switched the setting in Software & Updates to Notify me of a new Ubuntu version: For any new version, I also tried editing /etc/update-manager/release-upgrades and verified that Prompt=normal was indeed set.

I run

sudo apt-get update
sudo apt-get upgrade
sudo apt-get dist-upgrade

then

sudo do-release-upgrade -d

but it always returns:

sudo do-release-upgrade
Checking for a new Ubuntu release
Upgrades to the development release are only
available from the latest supported release.

This is not a duplicate of the previous question; the path for Ubuntu GNOME is 16.04.3 to 17.04. There is no 16.10 release of Ubuntu GNOME, so I'm not skipping any release versions.

do sudo update-manager -c in order to update from 16.04 to 17.04