Missing bot permissions
Missing Jiri bot permissions are common issue causing problems with notifications. Especially in some Discord server configurations, our Jiri bot does not get Send messages permission by default when joining the server. You need to add this permission manually in such case.
If the bot was missing Send messages permission the last time it tried to send a notification, then you will see an error message next to the channel connection (on the Discord Jira project settings page):
To fix this problem, go to your server settings and edit Jiri bot role:
Find Send Messages permission and enable it:
Test if everything works by triggering the notification again. You should now receive a notification to the selected channel, and the error message on Discord Jira project settings page should disappear.
To double check it, you can also go to your Discord server settings again, this time opening Integrations page and making sure that Jiri bot has Send messages permission: