Troubleshooting Slack alerts

TIR shows a Slack error when you use Test URL or Test Token in the integration form. A live alert that fails does so silently, so test again when alerts stop arriving.

What you see	Likely cause	What to do
The test message does not arrive (Webhook)	The webhook URL is incomplete or wrong	Copy the full URL again from Incoming Webhooks in the Slack app. It starts with https://hooks.slack.com/services/. Check that the channel exists.
The test message does not arrive (Token)	The bot has not joined the channel	In the channel, run /invite @<your app name>.
channel_not_found	The Channel ID is wrong	Enter the Channel ID, such as C12345678, not the channel name.
missing_scope	The bot token has no chat:write scope	Under OAuth & Permissions in the Slack app, add chat:write, then install the app again.
Alerts stopped arriving after they worked	The webhook URL was regenerated in Slack	Update the Webhook URL in the monitoring integration.
Messages go to the wrong channel	The Channel ID is wrong, or the webhook was made for another channel	Check the Channel ID, or create a webhook for the right channel.
The bot posts in public channels but not in a private one	The bot has not joined the private channel	Run /invite @<your app name> inside the private channel.

TIR also checks the format before it saves. A Slack webhook URL must start with https://hooks.slack.com/services/, and a bot token must start with xoxb-. A Channel ID must start with C, G, or D, followed by at least eight capital letters or digits.

See Send alerts to Slack for the full setup.