wp-admin: You do not have sufficient permissions to access this page

When migrating a Wordpress instalation some things could go wrong.

If you changed the table prefix, you might be getting this error when logging in the wordpress admin:

You do not have sufficient permissions to access this page

Solution:
Open phpmyadmin or something like that and go through the values in tables:
PREFIX_options
PREFIX_usermeta

find values that start with the old prefix, for example wp_ and change it to the new prefix.

in
wp_usermeta I changed all meta_key values from wp_* to newprefix_*
and in
wp_options I changed wp_user_roles to newprefix_user_roles.