diff --git a/litellm/llms/watsonx/common_utils.py b/litellm/llms/watsonx/common_utils.py
index d6f296c6081..c756be6d458 100644
--- a/litellm/llms/watsonx/common_utils.py
+++ b/litellm/llms/watsonx/common_utils.py
@@ -38,7 +38,11 @@ def generate_iam_token(api_key=None, **params) -> str:
         headers = {}
         headers["Content-Type"] = "application/x-www-form-urlencoded"
         if api_key is None:
-            api_key = get_secret_str("WX_API_KEY") or get_secret_str("WATSONX_API_KEY") or get_secret_str("WATSONX_APIKEY")
+            api_key = (
+                get_secret_str("WX_API_KEY")
+                or get_secret_str("WATSONX_API_KEY")
+                or get_secret_str("WATSONX_APIKEY")
+            )
         if api_key is None:
             raise ValueError("API key is required")
         headers["Accept"] = "application/json"
@@ -280,13 +284,9 @@ class IBMWatsonXMixin:
     def _prepare_payload(self, model: str, api_params: WatsonXAPIParams) -> dict:
         payload: dict = {}
         if model.startswith("deployment/"):
-            if api_params["space_id"] is None:
-                raise WatsonXAIError(
-                    status_code=401,
-                    message="Error: space_id is required for models called using the 'deployment/' endpoint. Pass in the space_id as a parameter or set it in the WX_SPACE_ID environment variable.",
-                )
-            payload["space_id"] = api_params["space_id"]
-            return payload
+            return (
+                {}
+            )  # Deployment models do not support 'space_id' or 'project_id' in their payload
         payload["model_id"] = model
         payload["project_id"] = api_params["project_id"]
         return payload
diff --git a/litellm/proxy/pass_through_endpoints/passthrough_endpoint_router.py b/litellm/proxy/pass_through_endpoints/passthrough_endpoint_router.py
index a02cacc3cc0..9335ce49bb7 100644
--- a/litellm/proxy/pass_through_endpoints/passthrough_endpoint_router.py
+++ b/litellm/proxy/pass_through_endpoints/passthrough_endpoint_router.py
@@ -110,7 +110,7 @@ class PassthroughEndpointRouter:
         self,
         project_id: str,
         location: str,
-        vertex_credentials: VERTEX_CREDENTIALS_TYPES,
+        vertex_credentials: Optional[VERTEX_CREDENTIALS_TYPES],
     ):
         """
         Add the vertex credentials for the given project-id, location
diff --git a/litellm/router.py b/litellm/router.py
index ae45212dccf..e8cba56b249 100644
--- a/litellm/router.py
+++ b/litellm/router.py
@@ -4740,13 +4740,9 @@ class Router:
                     or deployment.litellm_params.vertex_credentials
                 )
 
-                if (
-                    vertex_project is None
-                    or vertex_location is None
-                    or vertex_credentials is None
-                ):
+                if vertex_project is None or vertex_location is None:
                     raise ValueError(
-                        "vertex_project, vertex_location, and vertex_credentials must be set in litellm_params for pass-through endpoints"
+                        "vertex_project, and vertex_location must be set in litellm_params for pass-through endpoints."
                     )
                 passthrough_endpoint_router.add_vertex_credentials(
                     project_id=vertex_project,
diff --git a/tests/llm_translation/test_watsonx.py b/tests/llm_translation/test_watsonx.py
index d788541dada..e0c125a9017 100644
--- a/tests/llm_translation/test_watsonx.py
+++ b/tests/llm_translation/test_watsonx.py
@@ -206,7 +206,7 @@ def test_watsonx_deployment_space_id(monkeypatch, watsonx_chat_completion_call,
 
     assert mock_post.call_count == 1
     json_data = json.loads(mock_post.call_args.kwargs["data"])
-    assert my_fake_space_id == json_data["space_id"]
+    assert my_fake_space_id not in json_data
 
 
 def test_watsonx_deployment_space_id_embedding(monkeypatch, watsonx_embedding_call):
@@ -217,4 +217,4 @@ def test_watsonx_deployment_space_id_embedding(monkeypatch, watsonx_embedding_ca
 
     assert mock_post.call_count == 1
     json_data = json.loads(mock_post.call_args.kwargs["data"])
-    assert my_fake_space_id == json_data["space_id"]
+    assert my_fake_space_id not in json_data
diff --git a/tests/router_unit_tests/test_router_adding_deployments.py b/tests/router_unit_tests/test_router_adding_deployments.py
index 55481394bb1..6e2a7b79733 100644
--- a/tests/router_unit_tests/test_router_adding_deployments.py
+++ b/tests/router_unit_tests/test_router_adding_deployments.py
@@ -92,7 +92,7 @@ def test_initialize_deployment_for_pass_through_missing_params():
     # Test that initialization raises ValueError
     with pytest.raises(
         ValueError,
-        match="vertex_project, vertex_location, and vertex_credentials must be set",
+        match="vertex_project, and vertex_location must be set in litellm_params for pass-through endpoints",
     ):
         router._initialize_deployment_for_pass_through(
             deployment=deployment,