Update app.py

app.py

@@ -26,7 +26,10 @@ async def respond(
         async with aiohttp.ClientSession() as session:
             async with session.post(
                 "https://api.openai.com/v1/chat/completions",
-                headers={"Authorization": f"Bearer {ACCESS_TOKEN}"},
+                headers={
+                    "Authorization": f"Bearer {ACCESS_TOKEN}",
+                    "Content-Type": "application/json",
+                },
                 json={
                     "model": "NousResearch/Hermes-3-Llama-3.1-8B",
                     "max_tokens": max_tokens,