Zabbix – How to Fix Connection to Wrong Database

I have installed Zabbix on a CentOS 7 remote server, but I can't get it running.

I took a look at /var/log/zabbix/ and I get the following error:

1951:20190116:044530.834 [Z3001] connection to database 'zabbix' failed: [1045] Access denied for user 'zabbix'@'localhost' (using password: YES)

Now, the problem is that I DO have a database for zabbix, but it is named zabbixdb, not zabbix (as in the error message)

I tried to re-run the setup page and entered zabbixdb, but still nothing. Also, the /etc/zabbix/web/zabbix.conf.php is correctly configured

global $DB;

$DB['TYPE']     = 'MYSQL';
$DB['SERVER']   = '127.0.0.1';
$DB['PORT']     = '0';
$DB['DATABASE'] = 'zabbixdb';
$DB['USER']     = 'zabbixuser';
$DB['PASSWORD'] = '[my_pass_here]';

// Schema name. Used for IBM DB2 and PostgreSQL.
$DB['SCHEMA'] = '';

$ZBX_SERVER      = '127.0.0.1';
$ZBX_SERVER_PORT = '10051';
$ZBX_SERVER_NAME = 'SV Zabbix Server';

$IMAGE_FORMAT_DEFAULT = IMAGE_FORMAT_PNG;

I doubled checked and zabbixdb DOES exist and user zabbixuser has all the privileges over it.

GRANT ALL PRIVILEGES ON `zabbixdb`.* TO 'zabbixuser'@'localhost'                                                  

What others reasons could be? Somehow zabbix has access, because it has created tables in the zabbixdb, but can't use them.

EDIT: The Solution

As it turns out, I followed the tutorial's instructions blindly. Thank you @Zatarra for the solution.

My problem was that when I wrote the DB's credentials, I wrote them exactly at the top of the file, while they where also present at a lower level, and thus, when read, were overwritten in memory.

I solved this by modifying the variables present at the lower level in the file.