Contact form 7 bootstrap validation

I have my contact form 7 form in boostrap 4 style without <span> and <p> tags. On submit the validation of the form shows the message about unfilled inputs, but there are no messages and marker over inputs that are required.
I’m trying to do this with bootstrap validation, so I need to add the class .was-validated to form classes. I’m trying to use checkValidity(), to check the :invalid inputs, but it doesn’t work with Contact Form 7. Or I need to add classe to the invalid inputs.