Rackables - Database connection failed: SQLSTATE[HY000][1045] Access denied for user 'rackuser'@'localhost' (using password: YES)

Question

I'm getting the above error message while trying to use racktables. But when I log in via command line and check the mysql.user table, I see the following:

MariaDB [racktables]> select host, user, password from mysql.user;
+------------+----------+-------------------------------------------+
| host       | user     | password                                  |
+------------+----------+-------------------------------------------+
| localhost  | root     | *asdfasdfasdfasdfasdfasdfasdfasdfasdfasdf |
| racktables | root     |                                           |
| 127.0.0.1  | root     |                                           |
| ::1        | root     |                                           |
| localhost  |          |                                           |
| racktables |          |                                           |
| %          | root     |                                           |
| %          | rackuser | *asdfasdfasdfasdfasdfasdfasdfasdfasdfasdf |
| localhost  | rackuser | *asdfasdfasdfasdfasdfasdfasdfasdfasdfasdf |
| %          | admin    |                                           |
| localhost  | admin    | *asdfasdfasdfasdfasdfasdfasdfasdfasdfasdf |
| %          | repluser | *asdfasdfasdfasdfasdfasdfasdfasdfasdfasdf |
+------------+----------+-------------------------------------------+

In case it was a wrong password, I tried the following command:

MariaDB [racktables]> set password for 'rackuser'@'localhost' = PASSWORD('test');
ERROR 1133 (42000): Can't find any matching row in the user table
MariaDB [racktables]>

So I guess it's not a problem with the password but for some reason, it really thinks rackuser doesn't exist.

Any suggestions?

EDIT 1

This is what I did to get rid of the two blank users in case that's the problem:

MariaDB [racktables]> update mysql.user set user='test' where user='';
Query OK, 2 rows affected (0.01 sec)
Rows matched: 2  Changed: 2  Warnings: 0

So now I have this in the users table:

MariaDB [racktables]> select host, user, password from mysql.user;
+------------+----------+-------------------------------------------+
| host       | user     | password                                  |
+------------+----------+-------------------------------------------+
| localhost  | root     | *801C69EDAA2713E5028ABB0B25B78F53D10F7092 |
| racktables | root     |                                           |
| 127.0.0.1  | root     |                                           |
| ::1        | root     |                                           |
| localhost  | test     |                                           |
| racktables | test     |                                           |
| %          | root     |                                           |
| %          | rackuser | *676243218923905CF94CB52A3C9D3EB30CE8E20D |
| localhost  | rackuser | *E5506B53E906390547C639A6773B08B30FCA3EE3 |
| %          | admin    |                                           |
| localhost  | admin    | *676243218923905CF94CB52A3C9D3EB30CE8E20D |
| %          | repluser | *801C69EDAA2713E5028ABB0B25B78F53D10F7092 |
+------------+----------+-------------------------------------------+

And then I tried to set the password for the rackuser again but I'm still getting the same error:

MariaDB [racktables]> set password for 'rackuser'@'localhost' = PASSWORD('test');
ERROR 1133 (42000): Can't find any matching row in the user table