Transaction CSADMIN: Repository status offline

[symon_braunbaer]

Dear Experts,

what does it mean, if the status of a repository in CSADMIN is shown as offline ?

While writing this question, I found the following thread:

https://answers.sap.com/questions/10848575/content-repository-status-is-offline.html

Unfortunately none of the hints there helped. Clicking the lock button to start the repository didn't help a thing.
The MaxDB database of our Content Server is up and running, as shown a little lower in CSADMIN:

Many thanks for any useful tips and suggestions!