No new updates in 1.18-list empty

I'm receiving no updates in the update manager in 1.18, for about a month or more, list of updates in update manager is empty. Before, I was receiving updates regularly. Pressing "Check" doesn't help. The list is empty. Can you help?

Solved, thx.

There was a "stable" problem to upload new updates, related to the release of the new version of OMV.
I had a clean 1.0 installation, not an upgrade from 0.5. As recommended, following code fixed the problem:
rm -f /etc/apt/apt.conf.d/99openmediavault-release /etc/apt/apt.conf