HKH

I have good news. I found the specific reason why it was failing for you even after the SQL fix. Your user account (SOULAIMANE.TS.1997@GMAIL.COM) was listed in the database with the role of 'user', not 'admin'. This is why the system (correctly) blocked you from making changes. I have executed a script to force update your role to Admin. Please try again now. You should be able to add categories and books successfully.