Marketing Cloud Engagement | ContactKey and AddressID in GroupConnect (LINE) Import

In Marketing Cloud Engagement's GroupConnect(LINE), each contact is associated with a single AddressID. The most recently linked ContactKey for a given AddressID is treated as the active key; all previous ContactKeys for that AddressID are retained but become inactive.

Example)
Before import:
contactKey | addressId
auto-created-contactKey | addressId-001

Import file:
contactKey | addressId
user-defined-contactKey | addressId-001

After import:
contactKey | addressId
user-defined-contactKey | addressId-001
auto-created-contactKey | NULL

If an import file contains multiple records with the same AddressID but different ContactKeys, both ContactKeys are imported on the first run. Subsequent imports against the same AddressID will then fail with an error.

Example of Duplicate AddressID in the import file)
Before import:
contactKey | addressId
auto-created-contactKey | addressId-001

Import file:
contactKey | addressId
user-defined-contactKey-001 | addressId-001
user-defined-contactKey-002 | addressId-001

After import:
contactKey | addressId
user-defined-contactKey-001 | addressId-001
user-defined-contactKey-002 | addressId-001

Import again with the file below:
user-defined-contactKey-003 | addressId-001

After 2nd import:
contactKey | addressId
user-defined-contactKey-001 | addressId-001
user-defined-contactKey-002 | addressId-001
user-defined-contactKey-003 | addressId-001
※ This will not replace addressId-001 with a new Contact user-defined-contactKey-003 but will instead add the ContactKey with addressId-001 as well

A subsequent import targeting the same AddressID adds a new entry instead of replacing an existing one. Once this state is reached, it is no longer possible to replace a ContactKey for the same AddressID without first deleting the contacts.

Important: If the ContactKey in use is also active in other channels, deleting it will remove send history and tracking data across all those channels. For MobilePush channels in particular, deleting a ContactKey used by an SDK may interrupt communication between the SDK and the server.

Therefore, before importing contacts into a GroupConnect channel, customers must verify that the import file contains no duplicate AddressIDs.

If multiple ContactKeys are already registered to the same AddressID, use the SQL query in the Resolution section to identify the affected records.

To check the ChannelID, refer to this help page.