Rocket Validator looks for accesibility violations on your pages using the axe-core accessibility engine, hosted on our own servers and integrated into our web crawler. You don't need to buy an additional license, everything's already included in your Pro account at Rocket Validator.
A11Y check: Elements in the focus order need a role appropriate for interactive content
Accessibility rule: User input elements must have appropriate roles, whether native HTML or a custom widget, to convey to screen reader users their meaning when landed on and given focus. If a custom widget, appropriate ARIA role values must be used instead of abstract roles to correctly expose the purpose of the element.