diff --git a/app/schemas.py b/app/schemas.py
index 763f34143..6199c14bd 100644
--- a/app/schemas.py
+++ b/app/schemas.py
@@ -63,9 +63,16 @@ class UUIDsAsStringsMixin:
     @post_dump()
     def __post_dump(self, data):
         for key, value in data.items():
+
             if isinstance(value, UUID):
                 data[key] = str(value)
 
+            if isinstance(value, list):
+                data[key] = [
+                    (str(item) if isinstance(item, UUID) else item)
+                    for item in value
+                ]
+
 
 class BaseSchema(ma.ModelSchema):
 
diff --git a/tests/app/v2/inbound_sms/test_get_inbound_sms.py b/tests/app/v2/inbound_sms/test_get_inbound_sms.py
index dfd4ae0b9..7231ed9b9 100644
--- a/tests/app/v2/inbound_sms/test_get_inbound_sms.py
+++ b/tests/app/v2/inbound_sms/test_get_inbound_sms.py
@@ -1,7 +1,7 @@
 from flask import json, url_for
 
 from tests import create_authorization_header
-from tests.app.db import create_inbound_sms
+from tests.app.db import create_inbound_sms, create_service_inbound_api, create_service_callback_api
 
 
 def test_get_inbound_sms_returns_200(
@@ -31,6 +31,27 @@ def test_get_inbound_sms_returns_200(
     assert json_response == expected_response
 
 
+def test_get_inbound_sms_returns_200_when_service_has_callbacks(
+    client, sample_service
+):
+    create_service_inbound_api(
+        service=sample_service,
+        url="https://inbound.example.com",
+    )
+    create_service_callback_api(
+        service=sample_service,
+        url="https://inbound.example.com",
+    )
+
+    auth_header = create_authorization_header(service_id=sample_service.id)
+    response = client.get(
+        path='/v2/received-text-messages',
+        headers=[('Content-Type', 'application/json'), auth_header],
+    )
+
+    assert response.status_code == 200
+
+
 def test_get_inbound_sms_generate_page_links(client, sample_service, mocker):
     mocker.patch.dict(
         "app.v2.inbound_sms.get_inbound_sms.current_app.config",