It looks like you changed master admin permissions.
There are no way to fix them except direct change in database.
1. Access db using /usr/share/plesk-billing/billing-db
2. Check table 'admins' - admin with ID=1 must have field 'admin_is_active' set to 1
3. Check table 'admin_groups' - there must be a group 'root' with ID=1
4. Check table 'admin_group_rel' - there must be a row with admin_group_id=1 and admin_id=1
5. Check table 'admin_group_action_rel' - there must be a lot of actions for group with ID=1
Please check your db and post here where have you found misconfiguration. If you have everything OK for steps 2-4, I'll try to find what action is prohibited - send you the whole content of 'admin_group_action_rel' table