I have a problem and no idea where to look. For about a week, the connection to our (self-hosted) stash server suddenly stops working. In the jira-issues you do not see the branches. There is only the link "Create Branch". If you click on it, you end up on a Bitbucket login page.
My try: I deleted the link under "Application links" in Jira and Stash and rebuilt it. In Jira status is now "Connected".
But my problem persists. 
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There is some interesting information: I have defined the jira-workflow to trigger a transition when a branch is created. And that is exactly what happened. A branch was created in Stash and the transition was triggered in Jira:
Automated transition started progress on BLABLABLA (triggered when a branch was created in Stash)
So it looks like the connection is really correct and there is an error in Jira Cloud. ?