Musím počkať 90 dní na zapnutie knižnice Apple Music

Some services on some devices do not allow frequent switching of Apple IDs in use. After registering one Apple ID for such a service like iCloud Music Library, the user would have to wait 90 days before a different Apple ID can be used on that specific device with such a service; 90 days since the prior moment of activating those services with the previous Apple ID.

I understand that this can be disappointing when e.g. you bought a second-hand iPhone, where you have no control or insight to its prior use.

This support document details the mandatory 90 day wait time for “associated devices”. View associated devices in iTunes - Apple Support (last paragraph):

When you try to associate another Apple ID with a device that was already associated, you might see a message that says, "This device is associated with another Apple ID. You cannot associate this device with another Apple ID for [number] days." Depending on when you associated your device with your Apple ID, you might need to wait up to 90 days to associate the device with another Apple ID.