mysql.infoschema@localhost does not exist

DROP USER 'mysql.infoschema'@'localhost';

The rest of the solution is like previous answers.

1. Create the user again
2. Grant it permissions

3. mysql> CREATE USER 'mysql.infoschema'@'localhost' IDENTIFIED BY 'password';
   mysql> GRANT SELECT ON *.* TO `mysql.infoschema`@`localhost`;