diff --git a/wren-ai-service/src/providers/engine/wren.py b/wren-ai-service/src/providers/engine/wren.py
index 720499496..ba96edfb9 100644
--- a/wren-ai-service/src/providers/engine/wren.py
+++ b/wren-ai-service/src/providers/engine/wren.py
@@ -55,7 +55,7 @@ async def dry_run_sql(
             "source": os.getenv("WREN_IBIS_SOURCE"),
             "manifest": os.getenv("WREN_IBIS_MANIFEST"),
             "connection_info": orjson.loads(
-                base64.b64decode(os.getenv("WREN_IBIS_CONNECTION_INFO")).decode()
+                base64.b64decode(os.getenv("WREN_IBIS_CONNECTION_INFO"))
             )
             if os.getenv("WREN_IBIS_CONNECTION_INFO")
             else {},
@@ -92,9 +92,9 @@ async def dry_run_sql(
         async with session.get(
             f"{self._endpoint}/v1/mdl/dry-run",
             json={
-                "manifest": orjson.loads(
-                    base64.b64decode(properties.get("manifest", ""))
-                ),
+                "manifest": orjson.loads(base64.b64decode(properties.get("manifest")))
+                if properties.get("manifest")
+                else {},
                 "sql": remove_limit_statement(add_quotes(sql)),
             },
         ) as response: