Reset/remove validation error messages on modal form

Reset/remove validation error messages on modal form

I am using bootstrap 4.0 beta and validator 1.17.  I have a form in a bootstrap modal.  If I enter invalid data into a field (and validation error is displayed), then close the modal, then reopen the modal the error message is still there.  Man, I've searched to the end of the internet and tried so many things (mostly old versions), but nothing works.  I am using aspnet core which automatically loads and sets up the validator.

Any idea how I can clear the validation errors when the modal is first opened, or closed?

I've tried so many things so try to be using these bootstrap and validator versions before suggesting an fix.

Thanks.