When using the smc -cloudmanaged command to move Symantec Endpoint Security devices to a different ICDm it completes without error message and the clients do not move.
Symantec Endpoint Security where a password is configured in the Client Password Settings of the System Policy.
A password is set in the System Policy.
There are two options to workaround this issue:
1) A password is required when running an smc command. Refer to this techdocs page for proper synxtax.
https://techdocs.broadcom.com/us/en/symantec-security-software/endpoint-security-and-management/endpoint-protection/all/appendices/windows-commands-for-the-endpoint-protection-clien-v9567615-d19e6200.html
2) The password can be removed temporarily from the System Policy until all devices are moved to the new domain.