diff --git a/engine/apps/api/serializers/on_call_shifts.py b/engine/apps/api/serializers/on_call_shifts.py
index 7b561c38..9ef9130b 100644
--- a/engine/apps/api/serializers/on_call_shifts.py
+++ b/engine/apps/api/serializers/on_call_shifts.py
@@ -116,9 +116,9 @@ class OnCallShiftSerializer(EagerLoadingMixin, serializers.ModelSerializer):
                 )
             if frequency not in (CustomOnCallShift.FREQUENCY_WEEKLY, CustomOnCallShift.FREQUENCY_DAILY) and by_day:
                 raise serializers.ValidationError({"by_day": ["Cannot set days value for this frequency type"]})
-            if frequency == CustomOnCallShift.FREQUENCY_DAILY and by_day and interval > 1:
+            if frequency == CustomOnCallShift.FREQUENCY_DAILY and by_day and interval != 1:
                 raise serializers.ValidationError(
-                    {"interval": ["Cannot set interval > 1 if a days value is set for a daily frequency"]}
+                    {"interval": ["Interval must be 1 if a days value is set for a daily frequency"]}
                 )
 
     def _validate_rotation_start(self, shift_start, rotation_start):
diff --git a/engine/apps/api/tests/test_oncall_shift.py b/engine/apps/api/tests/test_oncall_shift.py
index 807eb8a6..945ecf50 100644
--- a/engine/apps/api/tests/test_oncall_shift.py
+++ b/engine/apps/api/tests/test_oncall_shift.py
@@ -789,7 +789,7 @@ def test_create_on_call_shift_invalid_data_interval(on_call_shift_internal_api_s
     assert response.status_code == status.HTTP_400_BAD_REQUEST
     assert response.data["interval"][0] == "Cannot set interval for non-recurrent shifts"
 
-    # by_day, daily, interval > 1
+    # by_day, daily, interval != 1
     data = {
         "title": "Test Shift 2",
         "type": CustomOnCallShift.TYPE_ROLLING_USERS_EVENT,
@@ -808,7 +808,7 @@ def test_create_on_call_shift_invalid_data_interval(on_call_shift_internal_api_s
     response = client.post(url, data, format="json", **make_user_auth_headers(user1, token))
 
     assert response.status_code == status.HTTP_400_BAD_REQUEST
-    assert response.data["interval"][0] == "Cannot set interval > 1 if a days value is set for a daily frequency"
+    assert response.data["interval"][0] == "Interval must be 1 if a days value is set for a daily frequency"
 
 
 @pytest.mark.django_db