Changed model to try to resolve the error

app.py

@@ -29,7 +29,7 @@ def build_chain():
     vectorstore = FAISS.from_documents(docs, embeddings)
     retriever = vectorstore.as_retriever(search_kwargs={"k": 3})
 
-    model_id = "Qwen/Qwen2.5-2.5B-Instruct"
+    model_id = "Qwen/Qwen2.5-1.5B-Instruct"
     tokenizer = AutoTokenizer.from_pretrained(model_id)
 
     # sigurnosno: ako nema pad token