We are aware that currently the client-side custom validation styles and tooltips are not accessible, since they are not exposed to assistive technologies. While we work on a solution, we’d recommend either using the server-side option or the default browser validation method.
When a required form input has not been populated, we used to get a warning message in previous versions of Bootstrap. The latest version of Bootstrap merely highlights the first non-validated field. This is not a great problem.
The problem arises when stopping an email from being entered twice into the database using Validate. If the case arises (duplicate email) then the form is not submitted. But there is no message to warn the user of what has happened.
Does anybody (@Teodor) have any ideas on a workaround.