https://iprint:9443/iprintconfig not accessable after iPrint Appliance Upgrade from 4.2 Patch11 to 23.4

the Migrate Existing iPrint Appliance Task runs without errors.

After the restart, all services are started, management via iManager is possible, users can print!

Only the https://iprint:9443/iprintconfig cannot be accessed.

We also tried to Upgrade the Appliance to 24.3 via Update Channel, but same problem.