fixed the app

app.py

@@ -70,6 +70,7 @@ st.set_page_config(page_title="Haystack Demo", page_icon="https://haystack.deeps
 # Persistent state
 set_state_if_absent("question", DEFAULT_QUESTION_AT_STARTUP)
 set_state_if_absent("answer", DEFAULT_ANSWER_AT_STARTUP)
+set_state_if_absent("results", None)
 
 
 # Small callback to reset the interface in case the text of the question changes
@@ -145,7 +146,7 @@ if run_pressed:
         ):
             try:
                 st.session_state.results  = query(
-                    question, top_k_reader=top_k_reader, top_k_retriever=top_k_retriever
+                    pipe, question, top_k_reader=top_k_reader, top_k_retriever=top_k_retriever
                 )
             except JSONDecodeError as je:
                 st.error("👓    An error occurred reading the results. Is the document store working?")
@@ -154,7 +155,7 @@ if run_pressed:
                 if "The server is busy processing requests" in str(e) or "503" in str(e):
                     st.error("🧑‍🌾    All our workers are busy! Try again later.")
                 else:
-                    st.error("🐞    An error occurred during the request.")
+                    st.error(f"🐞    An error occurred during the request. {str(e)}")
 
 
 if st.session_state.results: