diff --git a/modules/ppcp-api-client/src/ApiModule.php b/modules/ppcp-api-client/src/ApiModule.php
index 12cdd12a6..be55b951e 100644
--- a/modules/ppcp-api-client/src/ApiModule.php
+++ b/modules/ppcp-api-client/src/ApiModule.php
@@ -113,23 +113,16 @@ class ApiModule implements ServiceModule, ExtendingModule, ExecutableModule {
 			'woocommerce_paypal_payments_flush_api_cache',
 			static function () use ( $c ) {
 				$caches = array(
-					'api.paypal-bearer-cache'      => array(
-						PayPalBearer::CACHE_KEY,
-					),
-					'api.client-credentials-cache' => array(
-						SdkClientToken::CACHE_KEY,
-					),
+					'api.paypal-bearer-cache',
+					'api.client-credentials-cache',
+					'settings.service.signup-link-cache',
 				);
 
-				foreach ( $caches as $cache_id => $keys ) {
+				foreach ( $caches as $cache_id ) {
 					$cache = $c->get( $cache_id );
 					assert( $cache instanceof Cache );
 
-					foreach ( $keys as $key ) {
-						if ( $cache->has( $key ) ) {
-							$cache->delete( $key );
-						}
-					}
+					$cache->flush();
 				}
 			}
 		);
diff --git a/modules/ppcp-api-client/src/Helper/Cache.php b/modules/ppcp-api-client/src/Helper/Cache.php
index 3b831ea00..e77f78825 100644
--- a/modules/ppcp-api-client/src/Helper/Cache.php
+++ b/modules/ppcp-api-client/src/Helper/Cache.php
@@ -5,7 +5,7 @@
  * @package WooCommerce\PayPalCommerce\ApiClient\Helper
  */
 
-declare( strict_types=1 );
+declare( strict_types = 1 );
 
 namespace WooCommerce\PayPalCommerce\ApiClient\Helper;
 
@@ -48,8 +48,9 @@ class Cache {
 	 *
 	 * @return bool
 	 */
-	public function has( string $key ): bool {
+	public function has( string $key ) : bool {
 		$value = $this->get( $key );
+
 		return false !== $value;
 	}
 
@@ -58,20 +59,47 @@ class Cache {
 	 *
 	 * @param string $key The key.
 	 */
-	public function delete( string $key ): void {
+	public function delete( string $key ) : void {
 		delete_transient( $this->prefix . $key );
 	}
 
 	/**
 	 * Caches a value.
 	 *
-	 * @param string $key The key under which the value should be cached.
-	 * @param mixed  $value The value to cache.
+	 * @param string $key        The key under which the value should be cached.
+	 * @param mixed  $value      The value to cache.
 	 * @param int    $expiration Time until expiration in seconds.
 	 *
 	 * @return bool
 	 */
-	public function set( string $key, $value, int $expiration = 0 ): bool {
+	public function set( string $key, $value, int $expiration = 0 ) : bool {
 		return (bool) set_transient( $this->prefix . $key, $value, $expiration );
 	}
+
+	/**
+	 * Flushes all items of the current "cache group", i.e., items that use the defined prefix.
+	 *
+	 * @return void
+	 */
+	public function flush() : void {
+		global $wpdb;
+
+		// Get a list of all transients with the relevant "group prefix" from the DB.
+		$transients = $wpdb->get_col(
+			$wpdb->prepare(
+				"SELECT option_name FROM $wpdb->options WHERE option_name LIKE %s",
+				$wpdb->esc_like( '_transient_' . $this->prefix ) . '%'
+			)
+		);
+
+		/**
+		 * Delete each cache item individually to ensure WP can fire all relevant
+		 * actions, perform checks and other cleanup tasks and ensures eventually
+		 * object cache systems, like Redis, are kept in-sync with the DB.
+		 */
+		foreach ( $transients as $transient ) {
+			$key = str_replace( '_transient_' . $this->prefix, '', $transient );
+			$this->delete( $key );
+		}
+	}
 }