Login Session Sharing WordPress Multiple Installations

Hello Everyone,

I am on WordPress 4.4.2, I have multiple wordpress installations (Not Multisite)

1st Installation :- https://www.example.com
2nd installation :- https://www.example.com/blog/

I have pasted this in my Wp-Config file of 2nd Installation :-
define(‘CUSTOM_USER_TABLE’, ‘wp_users’);
define(‘CUSTOM_USERMETA_TABLE’, ‘wp_usermeta’);
define(‘COOKIE_DOMAIN’, ‘.example.com’);
define(‘COOKIEPATH’, ‘/’);

Problem :- The issue is that after pasting above code in 2nd WordPress Installation’s Wp-Config file, login table is shared, that means users are manually able to login. However, when we sign in to first installation the session is not shared on to the second installation. I feel there is some problem with the cookies. Could anyone please help me ?

Regards,
Tejas