Hello,
I am not seeing the Slack Notification [Enterprise] Option. I looked through the previous post from Nov '20 and it does not solve my issue. I installed Graylog 4.0 open source via apt on Debian, then upgraded to trial enterprise license via apt install graylog-enterprise-plugin and graylog-enterprise-integrations-plugin. In the notifications configuration, I can see a script notification [Enterprise] option, but nothing for Slack. I verified that that enterprise plugins and enterprise-integrations were installed. Am I missing something?