Suddenly Gnome Keyring doesn't handle ssh anymore


I’ve been using Ubuntu MATE 18.04 for a few weeks; suddently, a couple of days ago, the Gnome Keyring stopped handling my SSH passphrase. I definitely didn’t mess with the system configuration.

The autostart entry is correctly setup (it wasn’t changed). I’ve tried to launch it manually, but I get errors like the following:

couldn't connect to control socket at: /run/user/1000/keyring/control: Connection refused
couldn't access control socket: /run/user/1000/keyring/control: No such file or directory

Does anybody has any suggestion on how to proceed? It’s very annoying having to type my (long) ssh passphrase many times every day.