Error when saving the ALE distribution model in child system &1

What causes this issue?

The ALE distribution model used by the Central User Administration
could not be distributed to child system &v1&.

How to fix this error?

In the central system, start transaction BD64. Distribute the ALE
distribution model manually.
After successful distribution, restart transaction SCUA. Include the
child system &v1& in the system landscape again. Choose <ZK>Save</> to
activate the Central User Administration.

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