Redmine

Steps:
1. Display an issue in Redmine
2. Edit it with a note so that Redmine sends a mail to at least one user, and before saving it, unplug the configured SMTP server
3. Save the changes
Results :
We end up with

F, [2015-11-12T15:31:48.599086 #32243] FATAL -- : 
Net::OpenTimeout (execution expired):
  app/models/mailer.rb:455:in `deliver_mail'
  config/initializers/10-patches.rb:154:in `deliver'
  app/models/mailer.rb:95:in `block (2 levels) in deliver_issue_edit'
  app/models/issue.rb:909:in `block in each_notification'
  app/models/issue.rb:908:in `each'
  app/models/issue.rb:908:in `each_notification'
  app/models/mailer.rb:94:in `block in deliver_issue_edit'
  app/models/journal.rb:90:in `block in each_notification'
  app/models/journal.rb:88:in `each'
  app/models/journal.rb:88:in `each_notification'
  app/models/mailer.rb:93:in `deliver_issue_edit'
  app/models/journal.rb:302:in `send_notification'
  app/models/journal.rb:67:in `save'
  app/models/issue.rb:1623:in `create_journal'
  app/models/issue.rb:175:in `create_or_update'
  app/controllers/issues_controller.rb:489:in `block in save_issue_with_child_records'
  app/controllers/issues_controller.rb:477:in `save_issue_with_child_records'
  app/controllers/issues_controller.rb:187:in `update'
  lib/redmine/sudo_mode.rb:63:in `sudo_mode'

and the user gets an Error 500 page, and calls the admin.

It would be nicer to save the changes and flash an error that the mail could not be sent.