Hi, thanks for your answer.
Processing UsersController#create (for 79.208.95.54 at 2015-02-25 19:05:46) [POST]
Parameters: {"authenticity_token"=>"[FILTERED]", "controller"=>"users", "action"=>"create", "domain_id"=>"8", "commit"=>"Create", "record"=>{"password1_confirmation"=>"[FILTERED]", "fullname"=>"test", "name"=>"test", "quota"=>"1024", "password1"=>"[FILTERED]"}, "eid"=>"65d59ae24bea67220f4314a0d0e5705e", "_"=>""}
Domain Load (1.7ms) SELECT * FROM `domains` WHERE (`domains`.`id` = 8)
SQL (0.6ms) BEGIN
User Load (13.6ms) SELECT `users`.id FROM `users` WHERE (LOWER(`users`.`name`) = BINARY 'test' AND `users`.domain_id = 8) LIMIT 1
CACHE (0.0ms) SELECT * FROM `domains` WHERE (`domains`.`id` = 8)
CACHE (0.0ms) SELECT `users`.id FROM `users` WHERE (LOWER(`users`.`name`) = BINARY 'test' AND `users`.domain_id = 8) LIMIT 1
SQL (1.3ms) SELECT count(*) AS count_all FROM `users`
User Create (5.2ms) INSERT INTO `users` (`email`, `home`, `name`, `fullname`, `priority`, `domain_id`, `password`, `policy_id`, `created_at`, `quota`, `updated_at`) VALUES('
te...@xxx.de', '/var/mailserv/mail/
xxx.de/test/home', 'test', 'test', 7, 8, '*********l', 1, '2015-02-25 19:05:46', 1024, '2015-02-25 19:05:46')
SQL (0.1ms) BEGIN
WebmailUser Create (0.0ms) Mysql::Error: Column 'alias' cannot be null: INSERT INTO `users` (`user_id`, `last_login`, `alias`, `created`, `mail_host`, `preferences`, `language`, `username`) VALUES(NULL, '2015-02-25 19:05:46', NULL, '2015-02-25 19:05:46', 'localhost', 'a:2:{s:16:\"message_sort_col\";s:4:\"date\";s:18:\"message_sort_order\";s:4:\"DESC\";}', 'en_US', '
te...@xxx.de')
SQL (0.3ms) ROLLBACK
SQL (12.2ms) ROLLBACK
ActiveRecord::StatementInvalid (Mysql::Error: Column 'alias' cannot be null: INSERT INTO `users` (`user_id`, `last_login`, `alias`, `created`, `mail_host`, `preferences`, `language`, `username`) VALUES(NULL, '2015-02-25 19:05:46', NULL, '2015-02-25 19:05:46', 'localhost', 'a:2:{s:16:\"message_sort_col\";s:4:\"date\";s:18:\"message_sort_order\";s:4:\"DESC\";}', 'en_US', '
te...@xxx.de')):
app/models/user.rb:31:in `after_create'