Problem installing nexcloud admin/db user

Hi to all
i just followed the admin manual for installing “nextcloud” over a ovh vps with ubuntu 18.04 server on it.

I do not have a domain but just a name for the machine instead that an ip. And i configured all as suggested by the admin manual.

I add a db and a specific user to my mysql server.

i tried by ssh to install nexcloud by this command:

sudo -u www-data php occ maintenance:install --database *
“mysql” --database-name “nextcloud” --database-user “user1” --database-pass *
“XXXXXXX” --admin-user “adminNextCloud” --admin-pass “YYYYYYY”*

this command give me back this error:

Error while trying to create admin user: Failed to connect to the database: An exception occurred in driver: SQLSTATE[HY000] [1045] Access denied for user ‘oc_adminCloud2’@‘localhost’ (using password: YES)

first question:
who and where someone putting the prefix “oc_” on my user? and who puts “2” at the end of the user name, and why.

I’ve tried to delete some strange field on “config.php” but not seems to fixes my problem.

I’ve the same problem via web installer. And the web installer give me some warning about the .htaccess file, but is owned by www:data and seems configured as requested.

thanks to all.