Hi @rui - Welcome to the Tulip Community 
- we are happy you are here!
I am not sure if I fully understand your question, could you provide more details about the issue you are having while trying to write your SQL connector function? This Knowledge Base article provides a guide for getting started if you haven’t seen it before! How to Write a SQL Connector Function
Also, it looks like the error you are receiving someone has posted about before on Community and they were able to resolve the issue - see the link to that thread here "Address 127.0.0.1 resolved to 127.0.0.1, which is forbidden" Why it's coming whenever I try to connect my local database?
Let me know if this helps!