I can not find these filesVia SSH, change SSL=OFF to SSL=ON in the .conf file.
If disabled for the user, change in file /usr/local/directadmin/data/users/USER/user.conf
If disabled for the domain, change in file /usr/local/directadmin/data/users/USER/domains/DOMAIN.TLD.conf
Account manager in user level??? As far as I know user level does not have any "account manager", next to that, enabling SSL (or disabling it) is done in Domain Manager when using user level.disabled SSL in user level
Account Manager - SSL Certificate - Disable