Hi @Johannes Binder ,
Welcome to Microsoft Q&A platform and thanks for using Azure Services.
Sorry that you ran into this issue.
As per the documentation, this error indicates that a management operation on the cache (like scaling/patching) has failed, and further cache management operations are blocked until the cache status is restored. Please note that the cache will be fully functional and available for all data commands during this time.
Please reach out to Azure support to help unblock management operations on your cache.
May I know if you have a support plan to raise support ticket?