After an operating system change (CentOS 5 to CentOS 6), my Python script
could no longer connect with mysql database. I get the following error...

mysql_exceptions.OperationalError: (1045, "Access denied for user 'foo'@
'localhost
' (using password: YES)")

I have granted all on all databases to this user.
I attempted to run mysql_upgrade.

I am stymied because according to another guy, he is successfully accessing
the same database with the same credentials as I am (but in a PHP script).

Can any of you suggest an explanation for this?

Thanks in advance!