Fix ssl issue

backend/whatsapp.py

@@ -497,7 +497,8 @@ class WhatsAppService:
 
         url = f"{self.base_url}/{self.phone_number_id}/messages"
         try:
-            async with httpx.AsyncClient() as client:
+            ssl_ctx = ssl.create_default_context(cafile=certifi.where())
+            async with httpx.AsyncClient(verify=ssl_ctx) as client:
                 response = await client.post(
                     url,
                     json=payload,