Solved
Hello,
A validation error generally means there is a syntax error that needs to be cleared; otherwise, Kepware can’t add this to runtime. This was the reason you were unable to see it in Quick Client, as it was not added to runtime.
Below are things you can check to make it work:
- Check the tag address syntax as per the driver help file.
- Some tags are “Read Only” and cannot be set to “Read/Write” access.
- The tag address may have been modified later, so please verify.

