diff --git a/backend_health.go b/backend_health.go
index d974bf4..883b68b 100644
--- a/backend_health.go
+++ b/backend_health.go
@@ -28,6 +28,7 @@ type BackendHealthManager struct {
 	consecutiveFails atomic.Int32
 	isHealthy        atomic.Bool
 	startupProbe     bool
+	readyOnce        sync.Once
 }
 
 // NewBackendHealthManager creates a new backend health manager
@@ -75,7 +76,7 @@ func (bhm *BackendHealthManager) WaitForBackendReady(timeout time.Duration) erro
 					"time_taken":  time.Since(deadline.Add(-timeout)).String(),
 				},
 			})
-			close(bhm.readinessChan)
+			bhm.readyOnce.Do(func() { close(bhm.readinessChan) })
 			return nil
 		}
 
@@ -98,6 +99,11 @@ func (bhm *BackendHealthManager) WaitForBackendReady(timeout time.Duration) erro
 		}
 	}
 
+	// Startup probe timed out. Main continues and starts the proxy anyway, and
+	// StartHealthChecking's goroutine is blocked on readinessChan — so release
+	// it here too, otherwise periodic health checks never begin and the
+	// backend can never be marked healthy again even after it recovers.
+	bhm.readyOnce.Do(func() { close(bhm.readinessChan) })
 	return fmt.Errorf("GraphQL backend did not become ready within %v", timeout)
 }
 
diff --git a/connection_resilience_test.go b/connection_resilience_test.go
index bb1b99c..c87b1db 100644
--- a/connection_resilience_test.go
+++ b/connection_resilience_test.go
@@ -265,3 +265,21 @@ func (suite *ConnectionResilienceTestSuite) TestRetryLogic() {
 func TestConnectionResilienceSuite(t *testing.T) {
 	suite.Run(t, new(ConnectionResilienceTestSuite))
 }
+
+// TestHealthChecksStartAfterStartupTimeout verifies that when the startup
+// readiness probe times out, readinessChan is still released so the
+// health-check goroutine (started by StartHealthChecking) proceeds and begins
+// periodic checking — otherwise the backend could never be marked healthy
+// again even after it recovers.
+func (suite *ConnectionResilienceTestSuite) TestHealthChecksStartAfterStartupTimeout() {
+	bhm := NewBackendHealthManager(cfg.Client.FastProxyClient, "http://invalid-url:99999", cfg.Logger)
+	err := bhm.WaitForBackendReady(200 * time.Millisecond)
+	suite.Error(err, "expected timeout for unreachable backend")
+
+	select {
+	case <-bhm.readinessChan:
+		// Released -> periodic health checks will begin.
+	case <-time.After(1 * time.Second):
+		suite.Fail("readinessChan not closed after startup timeout; health checks would never begin")
+	}
+}