When you say you've created some accounts by database, do you mean that you've accessed the database and manually altered it in some way, possibly by entering new profiles?
If yes, that will be your problem. The database is not designed to be manipulated in this way because information is entered in more than one place.
I suggest that you replace the database with your backup if you have one and enter the new profiles in the proper way.
Modzzz has a special module called Admin Add Member https://www.boonex.com/m/admin-add-member
or you can do it yourself the slow way. That is to add new members via the join form, but you will need a couple of email accounts to do this. All email addresses must be unique.
Do yourself a favour and install AntonLV's FREE Mandatory Confirmation and most of your spam issues will go away. https://www.boonex.com/m/Mandatory_Confirmation