fix api destination update
diff --git a/domain/src/main/java/org/apache/rocketmq/eventbridge/domain/model/apidestination/ApiDestinationService.java b/domain/src/main/java/org/apache/rocketmq/eventbridge/domain/model/apidestination/ApiDestinationService.java
index 0a1c9a0..e723524 100644
--- a/domain/src/main/java/org/apache/rocketmq/eventbridge/domain/model/apidestination/ApiDestinationService.java
+++ b/domain/src/main/java/org/apache/rocketmq/eventbridge/domain/model/apidestination/ApiDestinationService.java
@@ -101,7 +101,9 @@
             throw new EventBridgeException(EventBridgeErrorCode.ApiDestinationNotExist, apiDestinationDTO.getName());
         }
         ApiDestinationDTO oldApiDestination = getApiDestination(apiDestinationDTO.getAccountId(), apiDestinationDTO.getName());
-        if (StringUtils.isBlank(apiDestinationDTO.getConnectionName())) {
+        if (StringUtils.isNotBlank(apiDestinationDTO.getConnectionName())) {
+            connectionService.getConnection(apiDestinationDTO.getAccountId(), apiDestinationDTO.getConnectionName());
+        } else {
             apiDestinationDTO.setConnectionName(oldApiDestination.getConnectionName());
         }
         if (apiDestinationDTO.getApiParams() == null) {