In Marketing Cloud Engagement - GroupConnect, due to the LINE API specifications used for sending, tracking "read (open)" status is not possible.
This article explains how to implement per-subscriber URL click tracking as an alternative to read tracking.
While read tracking is not available, it is possible to track whether a URL link within a message was clicked per subscriber.
To do this, append a parameter to the destination URL that identifies the individual subscriber, and use an analytics tool on the destination side to perform the tracking.
%%LINE_ADDRESS_ID%%)
https://[destination-site-url]?[parameter-name]=%%LINE_ADDRESS_ID%%
LINE_ADDRESS_ID) clicked the link at the destination.005228127

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