Update app.py

demo.queue(max_size=32, concurrency=1)

app.py

@@ -202,7 +202,7 @@ with gr.Blocks(title="PDF Q&A Chatbot") as demo:
     ask_button.click(answer_question, inputs=[question, state], outputs=answer)
 
 # Limit concurrency (HF-compatible)
-demo.queue(concurrency_count=1)
+demo.queue(max_size=32, concurrency=1)
 
 if __name__ == "__main__":
     demo.launch()