How I can allow my user to be connected via `localhost` when I ssh tunnel my Db connection?

In a server that I do not have admin access I managed to make an ssh tunnel as:

ssh -N -L 33308:127.0.0.1:3306 user@example.com

Then I attempt to connect into mysql via the tunnel:

mysql -u testusr -p -h 127.0.0.1 -P 33308 testdb

By I ended getting the error:

ERROR 1045 (28000): Access denied for user 'testusr'@'127.0.0.1' (using password: YES)

But once I have a shell session upon DB I manage to connect into mysql like this:

mysql -u testusr -p -h localhost testdb
mysql>

But I am unable to connect like this:

mysql -u testusr -p -h 127.0.0.1 testdb
ERROR 1045 (28000): Access denied for user 'testusr'@'127.0.0.1' (using password: YES)

Meaning that testusr is able to be connected via providing localhost as domain upon connection. So how I can setup the tunnel in order to be able to connect as?

mysql -u testusr -p -h localhost -P 33308 testdb

Upon my local machine?