Hello everyone, iam really not the backend or php guy. I started having an error when i try to view a user's details or to create a new user from OctoberCMS user plugin backend. Here is the error i see, evereything else seems to work normally :

We're sorry, but an unhandled error occurred. Please see the details below.

Cannot modify header information - headers already sent by (output started at /home/cssninjaua/www/plugins/rainlab/user/controllers/users/preview.htm:47) (SQL: select * from `system_files` where `system_files`.`attachment_type` = Backend\Models\BrandSetting and `system_files`.`attachment_id` = 5 and `field` = favicon and `system_files`.`attachment_id` is not null order by `sort_order` asc limit 1)
/home/cssninjaua/www/vendor/laravel/framework/src/Illuminate/Database/Connection.php line 664