diff --git a/onchain/tokens/metadata.py b/onchain/tokens/metadata.py
index 32db697..3e98d21 100644
--- a/onchain/tokens/metadata.py
+++ b/onchain/tokens/metadata.py
@@ -175,9 +175,9 @@ async def _search_token_on_dexscreener(
 
                 # Filter by chain if specified
                 if chain:
-                    pairs = [pair for pair in pairs if pair["chainId"] == chain]
-                if len(pairs) == 0:
-                    return None
+        chain = chain.lower()
+        if chain not in SUPPORTED_CHAINS:
+            return None
 
                 token_address = pairs[0]["baseToken"]["address"]
                 token_chain = pairs[0]["chainId"]
diff --git a/server/fastapi_server.py b/server/fastapi_server.py
index 3b62382..383ad2d 100644
--- a/server/fastapi_server.py
+++ b/server/fastapi_server.py
@@ -84,13 +84,24 @@ def create_fastapi_app() -> FastAPI:
     app = FastAPI()
 
     # Configure CORS
-    app.add_middleware(
+     app.add_middleware(
         CORSMiddleware,
         allow_origins=[
             "https://bitquant.io",
             "https://www.bitquant.io",
-            r"^http://localhost:(3000|3001|3002|4000|4200|5000|5173|8000|8080|8081|9000)$",
-            r"^https://defi-chat-hub-git-[\w-]+-open-gradient\.vercel\.app$",
+            "http://localhost:3000",
+            "http://localhost:3001",
+            "http://localhost:3002",
+            "http://localhost:4000",
+            "http://localhost:4200",
+            "http://localhost:5000",
+            "http://localhost:5173",
+            "http://localhost:8000",
+            "http://localhost:8080",
+            "http://localhost:8081",
+            "http://localhost:9000",
+        ],
+        allow_origin_regex=r"^https://defi-chat-hub-git-[\w-]+-open-gradient\.vercel\.app$",
         ],
         allow_credentials=True,
         allow_methods=["*"],