diff --git a/woolist-phplist/includes/class-woolist-api.php b/woolist-phplist/includes/class-woolist-api.php
index 3cfe483..050091b 100644
--- a/woolist-phplist/includes/class-woolist-api.php
+++ b/woolist-phplist/includes/class-woolist-api.php
@@ -179,8 +179,10 @@ class WooList_API {
 		$subscriber_id = null;
 		$existing      = $this->subscriber_get_by_email( $email );
 
-		if ( ! is_wp_error( $existing ) && ! empty( $existing['id'] ) ) {
-			$subscriber_id = (int) $existing['id'];
+		// phpList wraps subscriber data inside a "data" key: {"status":"success","data":{"id":…}}
+		$existing_id = $existing['data']['id'] ?? $existing['id'] ?? null;
+		if ( ! is_wp_error( $existing ) && ! empty( $existing_id ) ) {
+			$subscriber_id = (int) $existing_id;
 			WooList_Logger::debug( 'Found existing subscriber  id=' . $subscriber_id . '  email=' . $email );
 		} else {
 			// Step 2: create a new subscriber.
@@ -192,7 +194,9 @@ class WooList_API {
 				return [ 'success' => false, 'subscriber_id' => null ];
 			}
 
-			$subscriber_id = isset( $added['id'] ) ? (int) $added['id'] : null;
+			// phpList wraps the new subscriber inside a "data" key.
+			$subscriber_id = isset( $added['data']['id'] ) ? (int) $added['data']['id']
+				: ( isset( $added['id'] ) ? (int) $added['id'] : null );
 
 			if ( $subscriber_id ) {
 				WooList_Logger::info( 'Created new subscriber  id=' . $subscriber_id . '  email=' . $email );