diff --git a/config/maintenance/maintenance.go b/config/maintenance/maintenance.go
index fe721477..dc66fefe 100644
--- a/config/maintenance/maintenance.go
+++ b/config/maintenance/maintenance.go
@@ -82,7 +82,7 @@ func (c *Config) ValidateAndSetDefaults() error {
 	if err != nil {
 		return err
 	}
-	if c.Duration <= 0 || c.Duration >= 24*time.Hour {
+	if c.Duration <= 0 || c.Duration > 24*time.Hour {
 		return errInvalidMaintenanceDuration
 	}
 	return nil
diff --git a/config/maintenance/maintenance_test.go b/config/maintenance/maintenance_test.go
index 7f97734e..76ef9eb2 100644
--- a/config/maintenance/maintenance_test.go
+++ b/config/maintenance/maintenance_test.go
@@ -211,6 +211,14 @@ func TestConfig_IsUnderMaintenance(t *testing.T) {
 			},
 			expected: true,
 		},
+		{
+			name: "under-maintenance-starting-22h-ago-for-24h",
+			cfg: &Config{
+				Start:    fmt.Sprintf("%02d:00", normalizeHour(now.Hour()-22)),
+				Duration: 24 * time.Hour,
+			},
+			expected: true,
+		},
 		{
 			name: "under-maintenance-starting-4h-ago-for-3h",
 			cfg: &Config{
@@ -236,6 +244,15 @@ func TestConfig_IsUnderMaintenance(t *testing.T) {
 			},
 			expected: false,
 		},
+		{
+			name: "not-under-maintenance-today-with-24h-duration",
+			cfg: &Config{
+				Start:    fmt.Sprintf("%02d:00", now.Hour()),
+				Duration: 24 * time.Hour,
+				Every:    []string{now.Add(48 * time.Hour).Weekday().String()},
+			},
+			expected: false,
+		},
 	}
 	for _, scenario := range scenarios {
 		t.Run(scenario.name, func(t *testing.T) {