Install the server as usual following the tutorial for Centos 7.2, Apache When instal ISPConfig3 Code: Admin password [admin]: 6pZZZZZZZSd Re-enter admin password : 6pZZZZZZZSd When finished, go to URL, and "Username or Password wrong." Well. Usually copy & paste all password for a machine and after save on my system. Never type passwords. Well, I go to change manually Go to mysql Code: MariaDB [(none)]> use dbispconfig; UPDATE sys_user SET passwort = md5('NEWPASSWORD') WHERE username = 'admin'; MariaDB [dbispconfig]>quit; Got to ISPConfig interface and COPY & PASTE password, and not work. On last test, NEWPASSWORD has not any extended character. Only letters and Numbers. Also, verifiy that user 'ispconfig' on /usr/local/ispconfig/interface/lib/config.inc.php can connect to mysql database 'dbispconfig' [SOLVED] After see log tail -f /var/log/ispconfig/auth.log and on this logs show Sucessful logins, with original password, Suspect Dashlane, an extension of Chrome for password storage. And indeed it was the cause.