Can’t be reached The connection was reset while password is correct


I installed the latest version of Nextcloud at rhel8, then integrated it with AD, and it works fine. Now I try to migrate the server to another network. I also replace the “/var/www/html/nextcloud/config/config.php” file and when I use the correct username/password I get the “This site can’t be reachedThe connection was reset.” error with no log ( I check httpd and nextcloud.log files ). but when I use the wrong password I got the “wrong password” error.

Do the service open connection outside during the authentication?? ( cause the second network is mostly restricted )