What causes "client not found" in gotify/server?

Verify the client ID still exists and is owned by the logged-in user, then restart the elevation flow from the UI

client not found

Error message

client not found

What it means

handleElevationCallback (api/oidc.go:264) returns HTTP 404 'client not found' when GetClientByID returns no client for elevate.ClientID, or the client exists but belongs to a different user (client.UserID != user.ID). This is a deliberate ownership/authorization guard, not a database failure.

Source

Thrown at api/oidc.go:264

		}
		auth.SetCookie(w, client.Token, auth.CookieMaxAge, a.SecureCookie)
		// A reverse proxy may have already stripped a url prefix from the URL
		// without us knowing, we have to make a relative redirect.
		// We cannot use http.Redirect as this normalizes the Path with r.URL.
		w.Header().Set("Location", "../../")
		w.WriteHeader(http.StatusTemporaryRedirect)
	}
	return gin.WrapF(rp.CodeExchangeHandler(rp.UserinfoCallback(callback), a.Provider))
}

func (a *OIDCAPI) handleElevationCallback(w http.ResponseWriter, elevate *pendingElevation, user *model.User) {
	client, err := a.DB.GetClientByID(elevate.ClientID)
	if err != nil {
		http.Error(w, fmt.Sprintf("database error: %v", err), http.StatusInternalServerError)
		return
	}
	if client == nil || client.UserID != user.ID {
		http.Error(w, "client not found", http.StatusNotFound)
		return
	}
	elevatedUntil := time.Now().Add(time.Duration(elevate.DurationSeconds) * time.Second)
	if err := a.DB.UpdateClientElevatedUntil(client.ID, &elevatedUntil); err != nil {
		http.Error(w, fmt.Sprintf("failed to elevate session: %v", err), http.StatusInternalServerError)
		return
	}

	// The UI rechecks the authentication when the tab is closed.
	w.WriteHeader(http.StatusOK)
	w.Header().Add("content-type", "text/html")
	io.WriteString(w, `<!DOCTYPE html>
<html lang="en">
<head>
  <title>Gotify Session Elevation</title>
  <meta charset="UTF-8" />
  <meta name="viewport" content="width=device-width,initial-scale=1" />
</head>

View on GitHub (pinned to 14bfc25627)

Solutions

Verify the client ID still exists and is owned by the logged-in user, then restart the elevation flow from the UI
If the client was deleted, create it again and elevate the new client
Do not reuse or share elevation URLs; each is bound to one user and one client
Check that the same database is being used across restarts/replicas
Confirm the elevation was initiated for the account you actually authenticated with at the provider

Defensive patterns

Strategy: validation

Validate before calling

// Before starting the elevation flow, confirm the client exists and is yours
client, err := db.GetClientByID(clientID)
if err != nil {
    return err // DB problem, different failure mode
}
if client == nil || client.UserID != currentUser.ID {
    // do not start the elevation; it is guaranteed to 404 at the callback
    return errors.New("client missing or not owned by current user")
}

Try / catch

const res = await fetch(elevateCallbackURL);
if (res.status === 404 && (await res.text()).includes('client not found')) {
  // client was deleted or belongs to another user: refresh client list,
  // re-create if needed, then start a NEW elevation flow
  await refreshClients();
  return startElevation();
}

Prevention

Verify the client still exists right before initiating elevation
Never share or replay elevation URLs across users or sessions
Refresh the client list after deletions so the UI never elevates a stale ID
Ensure all instances point at the same database
Log the ClientID and UserID on this 404 to diagnose ownership mismatches

When it happens

Trigger: During the OIDC elevation callback: (1) the client was deleted between starting the elevation (ElevateHandler) and completing the provider round-trip; (2) the elevation state references a client owned by another user, e.g. after the state was crafted/replayed for a different account; (3) a stale elevation request referencing an ID from a different database/environment; (4) wrong ClientID stored in the pending elevation.

Common situations: User deletes the client (or an admin purges it) while the elevation tab is open at the provider; replaying an old elevation URL after re-authenticating as a different user; pointing gotify at a restored/migrated database missing that client row.

Related errors

AI-assisted analysis of gotify/server@14bfc25627 (2026-09-05). Data as JSON: /api/errors/cad68cc552113106. Report an issue: GitHub.