This is a newer install of JSM Data Center 5.8.0 bundled with Jira Core 9.8.0.
I can create issues from the portal without a problem. I can not create or edit existing issues. In a working system when I hit edit the screen goes dark, I get the spinning icon, and then another window comes up with the issue details.
In this system - with both create and edit from the agent view the background goes dark but the window never comes up. The spinning icon locks.
The behavior is the same on different browsers (Chrome, Edge) as well as on different computers and for different users. Pop-up blockers have been verified to be turned off.
The side bar has also not been loading along with an error that says the same thing.
In the console view in Chrome there are many 400 errors, similar to this issue: https://confluence.atlassian.com/jirakb/elements-in-jira-server-fail-to-render-with-400-bad-request-error-860033769.html
Also - the really weird part - if I right click on the Create or Edit buttons and use "View in a new tab" the tab loads just fine and it all functions like I'd expect.
This is configured to run over HTTPS with IIS.
