Notification not work to slack with Redmine 4.0.2

[ZerooCool]

I use RVM and Redmine 4.0.2 with linux mint Tara :
https://wiki.visionduweb.fr/index.php?title=Installer_Redmine_sur_Debian_avec_RVM

Notifications are not send.

I have install the plugin and up the configuration plugin from redmine admin.
https://wiki.visionduweb.fr/index.php?title=Installer_Redmine_sur_Debian#redmine-hangouts-chat

Then i create a chan in Slack, a room, a username for the bot.
https://wiki.visionduweb.fr/index.php?title=Installer_Redmine_sur_Debian#Cr.C3.A9er_un_compte_et_un_projet_depuis_Slack

Notifications are not send to my Slack channel.

Environment:
Redmine version 4.0.2.stable
Ruby version 2.4.5-p335 (2018-10-18) [x86_64-linux]
Rails version 5.2.2.1
Environment production
Database adapter Mysql2
Mailer queue ActiveJob::QueueAdapters::AsyncAdapter
Mailer delivery smtp
SCM:
Subversion 1.9.5
Filesystem
Redmine plugins:
redmine_hangouts_chat 0.2