How can I add my migrated issues to a next-gen kanban board?

[Gabriel_Melo]

I've migrated over 4000 issues from an Old-gen Project to a Next-gen one, but all the issues only show up in the Backlog page (which is slow as hell, by the way – barely unusable).

All the issues have their states rightfully allocated, but they don't show up in the Kanban board. How can i make them appear there?

[Nic Brough -Adaptavist-]

There is something blocking the route from your server to Atlassian's marketplace server.

Sometimes, this is an aggressive firewall on the server, but the most common culprit is basic connectivity - there's no route between them, or it's been firewalled by a corporate or state firewall.