3169318 - Configuration Transport Center error: The target instance you entered is already paired with this instance

When you try to sync two instances using the Transport Center or Instance Sync tool, it gives the error message "The target instance you entered is already paired with this instance", even if the pairing doesn't exist.

SAP SuccessFactors HCM Suite

Instance Sync, Instance Pair, unable to use the Instance Sync, unable to pair the instances, cannot sync two instances, The target instance you entered is already paired with this instance, Delete Existing Instance Pair, Instance Sync issue, Instance Sync error, Instance Pair issue, Instance Pair error, CGC, Configuration Transport Center , KBA , LOD-SF-PLT-CGC , Configuration Center , LOD-SF-PLT-IST , Instance Sync Tool , Problem