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The plugin will create the Webhook to send contact information back to Guestline automatically, once you’ve activated the setting in the configuration panel (see above).
However, in order to synchronize unsubscriptions back to Guestline, the unsubscription settings in the Maileon account need to be adjusted:
Browse to Settings → Contact Management → Unsubscriber Management in your Maileon account
Add External ID and last name to the list of fields, which will not be anonymized
Add Email address, External ID and last name to the list of fields, which will be transferred to the unsubscriber database
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