Redmine

I'm experiencing some odd behavior in 3.4.2. When a user tries to change the "Assigned To " to anyone else they receive an Internal Error message with the log entry below. Everything had been working just fine prior. Now we get this error when you try and update "Assigned To:" anyone else if you you are the originator of the issue. Any help is appreciated!

Errno::ECONNREFUSED (Connection refused - connect(2) for "localhost" port 9292):
  plugins/redmine_app_notifications/app/models/app_notification.rb:13:in `deliver'
  plugins/redmine_app_notifications/lib/app_notifications_journals_patch.rb:32:in `block in create_app_notifications_after_create_journal'
  plugins/redmine_app_notifications/lib/app_notifications_journals_patch.rb:24:in `each'
  plugins/redmine_app_notifications/lib/app_notifications_journals_patch.rb:24:in `create_app_notifications_after_create_journal'
  app/models/journal.rb:82:in `save'
  app/models/issue.rb:1841:in `create_journal'
  app/models/issue.rb:212:in `create_or_update'
  app/controllers/issues_controller.rb:558:in `block in save_issue_with_child_records'
  app/controllers/issues_controller.rb:546:in `save_issue_with_child_records'
  app/controllers/issues_controller.rb:168:in `update'
  lib/redmine/sudo_mode.rb:63:in `sudo_mode'