Now that I read that article again, I might know why I had that problem.
After I installed the docker, an update for the docker was available, so I installed it.
And right after the update, that problem occured.
Seems that this would be the solution?
“It’s also important to not stop the Storj docker from the ui, but instead type docker stop -t 300 storagenode in the terminal. If using an autoupdater, make sure to also set its timeout to 300 before stopping.”
How do I change this timeout?