diff --git a/inboard/app/base/main.py b/inboard/app/base/main.py
index 1cd52be..36385a4 100644
--- a/inboard/app/base/main.py
+++ b/inboard/app/base/main.py
@@ -24,11 +24,10 @@ async def __call__(
             }
         )
         version = f"{sys.version_info.major}.{sys.version_info.minor}"
-        server = (
-            "Uvicorn"
-            if os.getenv("PROCESS_MANAGER") == "uvicorn"
-            else "Uvicorn, Gunicorn,"
-        )
+        process_manager = os.getenv("PROCESS_MANAGER")
+        if process_manager not in ["gunicorn", "uvicorn"]:
+            raise NameError("Process manager needs to be either uvicorn or gunicorn.")
+        server = "Uvicorn" if process_manager == "uvicorn" else "Uvicorn, Gunicorn,"
         message = f"Hello World, from {server} and Python {version}!"
         response: Dict = {"type": "http.response.body", "body": message.encode("utf-8")}
         await send(response)
diff --git a/tests/app/test_main.py b/tests/app/test_main.py
index df89ca2..18fa3b8 100644
--- a/tests/app/test_main.py
+++ b/tests/app/test_main.py
@@ -102,6 +102,18 @@ def test_get_asgi_uvicorn_gunicorn(
         assert response.status_code == 200
         assert response.text == "Hello World, from Uvicorn, Gunicorn, and Python 3.8!"
 
+    def test_get_asgi_incorrect_process_manager(
+        self, client_asgi: TestClient, monkeypatch: MonkeyPatch
+    ) -> None:
+        """Test `GET` request to base ASGI app with incorrect `PROCESS_MANAGER`."""
+        monkeypatch.setenv("PROCESS_MANAGER", "incorrect")
+        monkeypatch.setenv("WITH_RELOAD", "false")
+        assert os.getenv("PROCESS_MANAGER") == "incorrect"
+        assert os.getenv("WITH_RELOAD") == "false"
+        with pytest.raises(NameError) as e:
+            client_asgi.get("/")
+            assert str(e) == "Process manager needs to be either uvicorn or gunicorn."
+
     def test_get_root(self, clients: List[TestClient]) -> None:
         """Test a `GET` request to the root endpoint."""
         for client in clients: