Why formvalidation.io plugin doesn’t work with Vue 3?

I have used the formvalidation.io plugin in my Vue 2 app with Option API but then I updated the Vue version to 3 and started to use the Composition API it is not working anymore.

Here is how I am importing formvalidation.io plugin.

import formValidation from '@/assets/plugins/formvalidation/dist/es6/core/Core';
// FormValidation plugins
import Icon from '@/assets/plugins/formvalidation/dist/es6/plugins/Icon';
import Trigger from '@/assets/plugins/formvalidation/dist/es6/plugins/Trigger';
import Bootstrap from '@/assets/plugins/formvalidation/dist/es6/plugins/Bootstrap';
import SubmitButton from '@/assets/plugins/formvalidation/dist/es6/plugins/SubmitButton';

Then in my setup() function, I'm creating a validation instance.

const validation = formValidation(
   _signupForm,
   {
      fields: {
         ...
      },
      plugins: {
         trigger: new Trigger(),
         bootstrap: new Bootstrap(),
         icon: new Icon({
            valid: 'fa fa-check',
            invalid: 'fa fa-times',
            validating: 'fa fa-refresh'
         }),
         submitButton: new SubmitButton(),
       }
    
   }
);

I am using it the same way as it is shown in the official doc: https://formvalidation.io/guide/examples/integrating-with-vue

When I open the app I am getting this error in browser console.

classSet.js?c52a:1 Uncaught (in promise) TypeError: Cannot read property 'classList' of null
   at eval (classSet.js?c52a:1)
   at Array.forEach (<anonymous>)
   at s (classSet.js?c52a:1)
   at eval (classSet.js?c52a:1)
   at Array.forEach (<anonymous>)
   at c (classSet.js?c52a:1)
   at s.install (Framework.js?e18a:1)
   at l.registerPlugin (Core.js?b275:1)
   at eval (Core.js?b275:1)
   at Array.forEach (<anonymous>)

I guess that the formValidation.io doesn't support the vue3 but I didn't find any info about it.

Can you help?

Read more here: https://stackoverflow.com/questions/65716101/why-formvalidation-io-plugin-doesnt-work-with-vue-3