The old plugin worked with the old version of VK authorization. The old version of authorization methods and API are completely broken. The old plugin is not working and is outdated.
It’s not even about the domain changing from .com to .ru; the method itself was different. An application was created for authorization, and a VK group (similar to a Facebook group) was added to the application. The system was different, and now it’s completely gone. The old applications are blocked. Now everything is concentrated on id.vk.ru.