Redmine

Since last week, I have a problem using redmine_backlogs plugin in Redmine. When I try to log time on an issue, I have this error message:

an error occured, please check the server logs (Unprocessable Entity)

Checking production.log, I have these lines:

ActiveRecord::RecordInvalid (Validation failed: Temps passé n'est pas valide):
  plugins/redmine_backlogs/lib/backlogs_activerecord_mixin.rb:38:in journalized_update_attributes!'
  plugins/redmine_backlogs/app/models/rb_task.rb:138:in update_with_relationships'
  plugins/redmine_backlogs/app/controllers/rb_tasks_controller.rb:28:in update'
  lib/redmine/sudo_mode.rb:63:in sudo_mode'

Here are the information about my Redmine instance:

Environment:

Redmine version                3.4.5.stable

Ruby version                   2.2.4-p230 (2015-12-16) [x86_64-linux-gnu]

Rails version                  4.2.8

Environment                    production

Database adapter               Mysql2

SCM:

Subversion                     1.9.3

Mercurial                      3.7.3

Git                            2.7.4

Filesystem

Redmine plugins:

a_common_libs                  2.1.10

clipboard_image_paste          1.10

global_roles                   2.1.0

google_analytics_plugin        1.0.0

redmine_backlogs               v1.0.6

redmine_code_review            0.7.0

redmine_dmsf                   1.5.7 devel

redmine_drafts                 0.2.0

redmine_issue_templates        0.1.1

redmine_ldap_sync              2.0.8.devel.gf831737c23

redmine_my_page                0.1.10

redmine_scm                    0.5.1

redmine_xls_export             0.2.1.t9
Thank you for your help

Mathieu