Is it mandatory to fine tune a RAG model on custom dataset to generate realted responses for queries, i working on RAG code from the examples , when i use a custom datast=et it doesnot produce intended results for queries

is it mandatory to fine tune a RAG model on custom dataset to generate realted responses for queries, i working on RAG code from the examples , when i use a custom datast=et it doesnot produce intended results for queries