System with tenant &1 is already managed. Register with same client no.

What causes this issue?

A managed system that was registered to a central system is reset i.e.
that is does not contain any Web Service configuration data due to
system copy or new installation to replace old system. System can be
registered again to central system if the following prerequisites are
fulfilled:
1. Central system still has system as managed system (but it is not
functional anymore because missing configuration).
2. New System has the same client number and system identifier on
central system.
3. New System has the same tenant key, system key and business
application ID.
4. On new System there is no configuration created so far and new system
is not defined as central system.

System Response

How to fix this error?

You can use the report SRT_WSP_SET_BUSINESS_APPL_ID to set tenant key,
system key and business application ID.

Procedure for System Administrators

Error message extract from SAP system. Copyright SAP SE.