3
           
            
                
     
    
    Somebody suggested to add this code to mainfile.php
 ini_set('session.cookie_lifetime', 0); // Make session cookie persist until browser closes 
ini_set('session.use_only_cookies', 1); 
ini_set('session.use_trans_sid', 0); 
ini_set('session.cookie_samesite', 'Lax'); // Allow cross-site requests while maintaining some security  
Test if this would help, but don't leave the code in your mainfile.php, this is just for testing, so once you done, comment it out. 
If it doesn't work, comment it out, and try to change the "strict" to "Lax" for 
 'samesite' => 'strict',  
to:
 'samesite' => 'Lax',  
in /kernel/session.php
 if (PHP_VERSION_ID >= 70300) { 
            $options = [ 
                'lifetime' => $lifetime, 
                'path'     => '/', 
                'domain'   => XOOPS_COOKIE_DOMAIN, 
                'secure'   => $secure, 
                'httponly' => true, 
                'samesite' => 'strict', 
            ]; 
            session_set_cookie_params($options); 
        } else { 
            session_set_cookie_params($lifetime, '/', XOOPS_COOKIE_DOMAIN, $secure, true); 
        }  
Again, once you're done with testing, reverse to the original code, and let us know if any of it helped