slack integration: jira cloud doesn't show issue previews

[Sohee Won]

I connected Jira cloud(slack integration) with my slack channels successfully. 

It has no problem sending a message in public channel when issues update.

But it doesn't work to show issue previews

Jira cloud can show issue previews only via direct message with me. (I've connected)

I have no idea how fix it. 

(of course I checked 'automatically show previews' option) 

[Dave Solwold]

Have you tried typing in /jira unfurl to see if it is on? I would try that if you haven't yet.