Kentico 12 with B2C Session Time Out

I am using B2C as third party authenticator to access the website. Once i log out, the page is redirecting to the required logged-out page, but the poblem is the authentication is not terminated and if i clicked on the authentication provider again, no credentials is required and automatic logs me in. I created to a webpart under the redirected logged-out page where it is expiring the AppServiceAuthSession & ASP.NET_SessionId and still have same problem Ex: 1) I use google to login 2) log out 3) Close the browser and then open the link and click on google, then it auto sign me in