Can't create a snapshot of SLE-Module-Basesystem15-SP2-Updates

I’ve got problem when I want create a SMT snapshot of SLE-Module-Basesystem15-SP2-Updates. The initial mirror works but in the staging part it’s say it has never been mirrored thus no snapshots can be made. When I look at the initial directory the files are there.
This problem only occurs with this specific repository. All others work
The smt server is a SLES 12 SP5 with latest updates and the smt version is 3.0.42-52.38.1