diff --git a/app/server/server.py b/app/server/server.py
index 519b54a2..f74af1b4 100644
--- a/app/server/server.py
+++ b/app/server/server.py
@@ -1,10 +1,10 @@
 import json
 import logging
 import os
-import requests
+import requests  # type: ignore
 
 from starlette.config import Config
-from authlib.integrations.starlette_client import OAuth, OAuthError
+from authlib.integrations.starlette_client import OAuth, OAuthError  # type: ignore
 from starlette.middleware.sessions import SessionMiddleware
 from starlette.responses import RedirectResponse, HTMLResponse
 from fastapi.responses import JSONResponse
@@ -26,7 +26,7 @@
 from integrations.sentinel import log_to_sentinel
 from integrations import maxmind
 from server.event_handlers import aws
-from sns_message_validator import (
+from sns_message_validator import (  # type: ignore
     SNSMessageValidator,
 )
 from fastapi import Depends
@@ -424,8 +424,12 @@ def get_version(request: Request):
     return {"version": os.environ.get("GIT_SHA", "unknown")}
 
 
-def append_incident_buttons(payload, webhook_id):
-    payload.attachments = payload.attachments + [
+def append_incident_buttons(payload: WebhookPayload, webhook_id):
+    if payload.attachments is None:
+        payload.attachments = []
+    elif isinstance(payload.attachments, str):
+        payload.attachments = [payload.attachments]
+    payload.attachments += [
         {
             "fallback": "Incident",
             "callback_id": "handle_incident_action_buttons",
diff --git a/app/tests/server/test_server.py b/app/tests/server/test_server.py
index 24726600..e3af3c59 100644
--- a/app/tests/server/test_server.py
+++ b/app/tests/server/test_server.py
@@ -367,7 +367,7 @@ def test_get_version_known():
     assert response.json() == {"version": "foo"}
 
 
-def test_append_incident_buttons():
+def test_append_incident_buttons_with_list_attachments():
     payload = MagicMock()
     attachments = PropertyMock(return_value=[])
     type(payload).attachments = attachments
@@ -375,8 +375,10 @@ def test_append_incident_buttons():
     webhook_id = "bar"
     resp = server.append_incident_buttons(payload, webhook_id)
     assert payload == resp
-    assert attachments.call_count == 2
+    assert attachments.call_count == 4
     assert attachments.call_args_list == [
+        call(),
+        call(),
         call(),
         call(
             [
@@ -407,6 +409,76 @@ def test_append_incident_buttons():
     ]
 
 
+def test_append_incident_buttons_with_none_attachments():
+    payload = MagicMock()
+    payload.attachments = None
+    payload.text = "text"
+    webhook_id = "bar"
+
+    resp = server.append_incident_buttons(payload, webhook_id)
+
+    assert payload == resp
+    assert payload.attachments == [
+        {
+            "fallback": "Incident",
+            "callback_id": "handle_incident_action_buttons",
+            "color": "#3AA3E3",
+            "attachment_type": "default",
+            "actions": [
+                {
+                    "name": "call-incident",
+                    "text": "🎉   Call incident ",
+                    "type": "button",
+                    "value": "text",
+                    "style": "primary",
+                },
+                {
+                    "name": "ignore-incident",
+                    "text": "🙈   Acknowledge and ignore",
+                    "type": "button",
+                    "value": "bar",
+                    "style": "default",
+                },
+            ],
+        }
+    ]
+
+
+def test_append_incident_buttons_with_str_attachments():
+    payload = MagicMock()
+    payload.attachments = "existing_attachment"
+    payload.text = "text"
+    webhook_id = "bar"
+
+    resp = server.append_incident_buttons(payload, webhook_id)
+    assert payload == resp
+    assert payload.attachments == [
+        "existing_attachment",
+        {
+            "fallback": "Incident",
+            "callback_id": "handle_incident_action_buttons",
+            "color": "#3AA3E3",
+            "attachment_type": "default",
+            "actions": [
+                {
+                    "name": "call-incident",
+                    "text": "🎉   Call incident ",
+                    "type": "button",
+                    "value": "text",
+                    "style": "primary",
+                },
+                {
+                    "name": "ignore-incident",
+                    "text": "🙈   Acknowledge and ignore",
+                    "type": "button",
+                    "value": "bar",
+                    "style": "default",
+                },
+            ],
+        },
+    ]
+
+
 # Unit test the react app
 def test_react_app():
     # test the react app