Hi @RXR ,
Thank you for posting query in Microsoft Q&A Platform.
From error message it seems either table
NidSitesTestUpdatenot exists in SQL Db or User ID used in linked service to connect to SQL Db doesn't have permissions to access table
Kindly check above both the cases to resolve the issue. If tables exists in Db then make sure if permissions are there to work with that table for your user Id to perform select and updates.