diff --git a/fastchat/serve/gradio_web_server.py b/fastchat/serve/gradio_web_server.py
index 8941c6ecb..60d9f7ef2 100644
--- a/fastchat/serve/gradio_web_server.py
+++ b/fastchat/serve/gradio_web_server.py
@@ -328,7 +328,7 @@ def regenerate(state, request: gr.Request):
     logger.info(f"regenerate. ip: {ip}")
     if not state.regen_support:
         state.skip_next = True
-        return (state, state.to_gradio_chatbot(), "", None) + (no_change_btn,) * 5
+        return (state, state.to_gradio_chatbot(), "") + (no_change_btn,) * 5
     state.conv.update_last_message(None)
     return (state, state.to_gradio_chatbot(), "") + (disable_btn,) * 5
 
@@ -361,7 +361,7 @@ def add_text(state, model_selector, text, request: gr.Request):
 
     if len(text) <= 0:
         state.skip_next = True
-        return (state, state.to_gradio_chatbot(), "", None) + (no_change_btn,) * 5
+        return (state, state.to_gradio_chatbot(), "") + (no_change_btn,) * 5
 
     all_conv_text = state.conv.get_prompt()
     all_conv_text = all_conv_text[-2000:] + "\nuser: " + text
@@ -375,7 +375,7 @@ def add_text(state, model_selector, text, request: gr.Request):
     if (len(state.conv.messages) - state.conv.offset) // 2 >= CONVERSATION_TURN_LIMIT:
         logger.info(f"conversation turn limit. ip: {ip}. text: {text}")
         state.skip_next = True
-        return (state, state.to_gradio_chatbot(), CONVERSATION_LIMIT_MSG, None) + (
+        return (state, state.to_gradio_chatbot(), CONVERSATION_LIMIT_MSG) + (
             no_change_btn,
         ) * 5