ERROR 1604

I ssh into my server and try nto change the root password to gain access to my nextcloud installation.

I tried mysqld_safe --init-file=/etc/mysql/conf.d/mysql-init &

including mysql-init containing ALTER USER 'root'@'localhost' IDENTIFIED BY 'xxxxxxx'; resulted inthe following messages (taken from /var/log/syslog:)

Jul 6 19:58:18 srv01 mysqld: 2017-07-06 19:58:18 140524274704960 [Note] InnoDB: Percona XtraDB (http://www.percona.com) 5.6.35-80.0 started; log sequence number 1617265 Jul 6 19:58:18 srv01 mysqld: 2017-07-06 19:58:18 140524274704960 [Note] Plugin 'FEEDBACK' is disabled. Jul 6 19:58:18 srv01 mysqld: 2017-07-06 19:58:18 140524274704960 [Note] Recovering after a crash using tc.log Jul 6 19:58:18 srv01 mysqld: 2017-07-06 19:58:18 140524274704960 [Note] Starting crash recovery... Jul 6 19:58:18 srv01 mysqld: 2017-07-06 19:58:18 140524274704960 [Note] Crash recovery finished. Jul 6 19:58:18 srv01 mysqld: 2017-07-06 19:58:18 140523654326016 [Note] InnoDB: Dumping buffer pool(s) not yet started Jul 6 19:58:18 srv01 mysqld: 2017-07-06 19:58:18 140524274704960 [Note] Server socket created on IP: '127.0.0.1'. Jul 6 19:58:18 srv01 mysqld: ERROR: 1064 You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near 'USER 'root'@'localhost' IDENTIFIED BY 'sql4450';' at line 1 Jul 6 19:58:18 srv01 mysqld: 2017-07-06 19:58:18 140524274704960 [Note] /usr/sbin/mysqld: ready for connections. Jul 6 19:58:18 srv01 mysqld: Version: '10.1.23-MariaDB-9+deb9u1' socket: '/var/run/mysqld/mysqld.sock' port: 3306 Debian 9.0

What went wrong and why I cannot connect to the database resp. finish the installation of nextcloud??

I highly appreciate your answer to solve the problem, which keeps me busy since 2 days!

best regards, bleckie