Loop first installation on http://phpvms.ralp.it/install/step2

[ASX157]

After successfully passing the requirements and database access phases, the application goes into a loop in the database setup phase.
I noticed that strangely the credentials have the user name without any value. This is how the connection string looks like:
SQLSTATE[HY000] [1045] Access denied for user ''@'127.0.0.1' (using password: NO) (Connection: mysql, SQL: select table_name as `name`, (data_length + index_length) as `size`, table_comment as `comment`, engine as `engine`, table_collation as `collation` from information_schema.tables where table_schema = '' and table_type = 'BASE TABLE' order by table_name).
And as you can see, the username is not reported, which in my case is phpvms and which has successfully passed the db access test.
What am I doing wrong?

[ASX157]

I've solved installing as user no root.