At first you should check which users are allowed to access the database service:
MariaDB [(none)]> select user,host from mysql.user;
Now you should check which users are allowed to access which database:
MariaDB [(none)]> select user,host,db from mysql.db;
Keep in mind that “localhost” is not the same as “127.0.0.1” 
If necessary, aunt G will tell you how you could add missing access rights.