Why is the request from root not being fulfilled?

Question

MariaDB

Greetings!
I need to change the encoding of the table, do this

ALTER TABLE news  CONVERT TO CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci;

the result is Access denied for user 'root'@'localhost' to database 'information_schema'
while requesting

ALTER DATABASE `dbname` CHARACTER SET = utf8mb4 COLLATE = utf8mb4_unicode_ci;

is executed successfully.
I execute queries on a test base as root.