I will reinstall Discourse again (with a fresh server image) and will try to restore the backup again.
The 40% stucking was with the upload in Discourse directly, after that I copied the backup via SCP to the server.
Yes, that’s true, but I thought something important will be saved in the backup too. Now I don’t know which plugins I had installed in the old instance and how the settings were from the them.
The backup was from 6th December this year, so only a few days ago.