How do I fix error 1045

[Martin McGlensey]

How do I fix error 1045 "Access denied for root@localhost (using password yes).

Error ocurrs when I execute the statement GRANT ALL PRIVILEGES ON *.* TO `root`@`localhost` WITH GRANT OPTION;

It appears that root cannot grant privileges to any user. root does not appear to have GRANT privilege.

I'm using MySQL 8 on Linux Mint. I can log in to mysql OK.

Thanks,
Marty