Redmine

Good evening!
Established Redmine-3.3.0 (Ruby-2.1.0, Ubuntu-14.04).
In web-based interface, went under the admin user, created the project, but I can not create the issue, there is not even a button to create a issue. (I allowed myself to create a issue).
However, if you go along the way: My Page -> My Issues, there is "New issue" button there, but when you click on it throws an error:
Internal error

An error occurred on the page you were trying to access.
     If you continue to experience problems please contact your Redmine administrator for assistance.

If you are the Redmine administrator, check your log files for details about the error.

In the file production.log raises this error:

ActionView::Template::Error (undefined method `assignable_users' for nil:NilClass):
15: <% end >
16:
17: < if @issue.safe_attribute? 'assigned_to_id' >
18: <p><= f.select :assigned_to_id, principals_options_for_select(@issue.assignable_users, @issue.assigned_to), :include_blank => true, :required => @issue.required_attribute?('assigned_to_id') ></p>
19: < end >
20:
21: < if @issue.safe_attribute?('category_id') && @issue.project.issue_categories.any? %>
app/models/issue.rb:857:in `assignable_users'
app/views/issues/_attributes.html.erb:18:in `block in app_views_issues_attributes_html_erb__4517615176650408187_70172066171880'
app/helpers/application_helper.rb:1058:in `labelled_fields_for'
app/views/issues/_attributes.html.erb:1:in `_app_views_issues__attributes_html_erb__4517615176650408187_70172066171880'
app/views/issues/_form.html.erb:42:in `block in app_views_issues_form_html_erb__4080601247170473640_70172065970640'
app/helpers/application_helper.rb:1058:in `labelled_fields_for'
app/views/issues/_form.html.erb:1:in `_app_views_issues__form_html_erb__4080601247170473640_70172065970640'
app/views/issues/new.html.erb:11:in `block in app_views_issues_new_html_erb_3132125182747956704_70172065863360'
app/helpers/application_helper.rb:1051:in `labelled_form_for'
app/views/issues/new.html.erb:5:in `_app_views_issues_new_html_erb__3132125182747956704_70172065863360'
app/controllers/issues_controller.rb:129:in `block (2 levels) in new'
app/controllers/issues_controller.rb:128:in `new'
lib/redmine/sudo_mode.rb:63:in `sudo_mode'

Please, help solve this problem!
Thanks!