On the Jira Administration --> Backup Manager I tried to export my projects so that I could import them on our local jira server. However, I received the following error message:
Back up for server
Your site contains next-gen projects. Jira server products and Jira Data Center don't support these.
The recommendation is to move the issues into a classic project.
However I failed to create a classic project. I could not find this in the documentation.