diff --git a/includes/reader-activation/class-reader-activation.php b/includes/reader-activation/class-reader-activation.php
index e2c622dc27..c14f803c0c 100644
--- a/includes/reader-activation/class-reader-activation.php
+++ b/includes/reader-activation/class-reader-activation.php
@@ -462,21 +462,24 @@ public static function get_registration_newsletter_lists() {
 	/**
 	 * Get the newsletter lists that should be rendered after checkout.
 	 *
-	 * @param string $email Email address.
+	 * @param string $email_address Email address. Optional.
 	 *
 	 * @return array
 	 */
-	public static function get_post_checkout_newsletter_lists( $email ) {
+	public static function get_post_checkout_newsletter_lists( $email_address = '' ) {
 		$available_lists    = self::get_available_newsletter_lists();
 		$registration_lists = [];
+		$current_lists      = [];
 
 		if ( empty( $available_lists ) || ! method_exists( '\Newspack_Newsletters_Subscription', 'get_contact_lists' ) ) {
 			return [];
 		}
 
-		$current_lists = \Newspack_Newsletters_Subscription::get_contact_lists( $email );
-		if ( \is_wp_error( $current_lists ) || ! is_array( $current_lists ) ) {
-			return [];
+		if ( $email ) {
+			$current_lists = \Newspack_Newsletters_Subscription::get_contact_lists( $email );
+			if ( \is_wp_error( $current_lists ) || ! is_array( $current_lists ) ) {
+				return [];
+			}
 		}
 
 		foreach ( $available_lists as $list_id => $list ) {
@@ -1401,11 +1404,7 @@ public static function render_newsletters_signup_modal() {
 			return;
 		}
 
-		$email_address = self::get_logged_in_reader_email_address();
-		if ( ! $email_address ) {
-			return;
-		}
-
+		$email_address     = self::get_logged_in_reader_email_address();
 		$newsletters_lists = self::get_post_checkout_newsletter_lists( $email_address );
 		if ( empty( $newsletters_lists ) ) {
 			return;