Can’t access to Network Admin after 5.8

Replies: 0

Hey

After upgrading my website to WP 5.8 I got this problem, I can’t access to Network Admin Dashboard, it keeps asking me to log in over and over without showing me any error message.

I tried to repair and optimize the database, disabled plugins, and theme, restored the last known working backups before 5.8, edited and replaced htaccess file, I edited and added those lines to wp-config.php

define('ADMIN_COOKIE_PATH', '/'); 
define('COOKIEPATH', ''); 
define('SITECOOKIEPATH', ''); 
define('COOKIE_DOMAIN', false);

changed admin privilege in sitemeta at PHPMyAdmin to

a:1:{i:0;s:11:"username";}

I did the research for a similar problem and tried as many solutions as I can, I even called SiteGround support and we were working on this issue for almost an hour but with no solution.

anyone can help?

Best Regards.