After ugrading Kubuntu 20.10 (Groovy) to 21.04 (Hirsute), I started getting the following error when trying to build any Docker containers:
error: failed to solve: rpc error: code = Unknown desc = failed to solve with frontend dockerfile.v0: failed to create LLB definition: rpc error: code = Unknown desc = error getting credentials - err: exit status 1, out: `GDBus.Error:org.freedesktop.DBus.Error.ServiceUnknown: The name org.freedesktop.secrets was not provided by any .service files`
Various Googling pointed to the result; simply installing the gnome-keyring package resolved the problem:
apt -y install gnome-keyring
After doing that everything worked as expected.
EDIT: After using the OS some more, I realized that the problem was not limited just to Docker, any services using libsecret were broken. As I use KeePassXC with libsecret integration I took a look in the settings and it turns out the integration was disabled. I purged the gnome-keyring package again, killed the gnome-keyring service and enabled the KeePassXC integration and it all worked as usual.