Check out the solution in the video Schema validation failed: 'ISJSON' is not a recognized built-in function name. First, note the version of Microsoft SQL Server that we're using. This is key because we'll see this error if we're using an older version
Check out the highest-rated Automating ETL course on Udemy, if you're interested in data.
We will find that some environments are using legacy systems (this may have advantages in both cost and security). It's possible that we're trying to convert something with a function that is not present.
YouTube | Automating ETL | T-SQL In 2 Hours | Consumer Guide To Digital Security