Starting yesterday we are no longer receiving notifications to our slack channel.
I attempted to setup new notification integrations with both slack and discord. The flow would complete and after being redirected back to the Unity Integrations page the integration was not there. After doing this several times for both Slack and Discord it eventually worked.
Notifications are still not being sent. I selected all build events for cloud build.
Having the same problem, along with builds randomly failing and being cancelled. I think something must be on fire at Unity HQ.
We use custom notifications to send messages to Microsoft Teams and they didn’t work last night either so I guess something must be broken 
Also seeing no notifications as of last night at some point. We use them as part of our continuous integration system, so having them not work is a big issue for us right now.
Notifications are working now for us.
They are working for us now.