Login and Logout Issue With Multisite Subdomain

Hi, I just created a sub domain multisite. I followed the step by step
instruction on how to install a WordPress multisite. I already add a wild card sub domain in cpanel, setup the code in wp-config.php and .htaccess. I add a sub domain site:
example1.mysite.com and
example2.mysite.com.

I noticed that when I tried to logout a certain sub domain, it doesn’t logout me in other sub domain. When I sign in also to the main site, the other sub domain is not login. What could be the problem? It doesn’t let me do single sigin and single logout.

Can anyone help me? Having a hard time.

Any help is much appreciated.