--- title: "Troubleshoot execution issues" slug: "cloudfunctions-troubleshoot-execution" updated: 2026-09-17T09:18:06Z published: 2026-09-17T09:18:06Z canonical: "guide.ncloud-docs.com/cloudfunctions-troubleshoot-execution" --- > ## Documentation Index > Fetch the complete documentation index at: https://guide.ncloud-docs.com/llms.txt > Use this file to discover all available pages before exploring further. # Troubleshoot execution issues Available in Classic and VPC You might run into the following problems when using Cloud Functions: Find out causes and possible solutions. ## Cron execution error An action works in Cloud Functions but not in Cron. #### Cause There is no difference between Cron (Auto) and manual execution (Manual) of actions in Cloud Functions. However, you can forward the default parameter values to the connected action in the trigger level including the Cron trigger. On the other hand, when you execute an action manually, it is possible to forward the runtime parameter in the execution window, but is not possible to forward other parameters than the default parameters in the Cron trigger. #### Solution As other parameters than the default parameter cannot be forwarded in the Cron trigger, check if there are any parts that get and use the necessary parameter values within the code. ## Object Storage type trigger execution error I set an upload event in an Object Storage type trigger, but the trigger does not work. #### Cause There are 2 methods to upload files to Object Storage: regular upload and multipart upload. You can upload large files in the multipart upload method. If you set `ObjectCreated:PUT` in the event setting but not `ObjectCreated:COMPLETE_UPLOAD`, which is the event type for multipart uploads, the trigger may not work when a multipart upload occurs. #### Solution - For the multipart upload event trigger, add ObjectCreated:COMPLETE_UPLOAD event type. For how to add an event type, see [Object Storage type trigger](/docs/en/cloudfunctions-objectstorage-vpc) and [UploadPart API guides](https://api.ncloud-docs.com/docs/en/storage-objectstorage-uploadpart). - If the trigger still does not work even after you added the event type, forward the bucket name, object name, and time of upload to [Customer Support](https://www.ncloud.com/support/question/service). ## "cannot import name... " error An error in the format of "cannot import name..." occurs when running a Python action. #### Cause - Libraries are missing in the compressed code file. - The system library is missing. #### Solution **Missing libraries in compressed code file** Create an action by packaging with dependency files. For more information, see [Create action by packaging with dependency files](/docs/en/cloudfunctions-example-python#%EC%9D%98%EC%A1%B4%EC%84%B1%ED%8C%8C%EC%9D%BC%EC%9D%84%ED%95%A8%EA%BB%98%ED%8C%A8%ED%82%A4%EC%A7%95%ED%95%98%EC%97%AC%EC%95%A1%EC%85%98%EC%83%9D%EC%84%B1) in Cloud Functions examples > Create and utilize actions by runtime > Python guide. **Missing system library** This usually occurs when the Python libraries rely on different system libraries (*.so and *.dll) depending on the OS, when the Windows or macOS system libraries are included in the compressed file, or when there is no system library to refer to in the CF runtime image. Check for the missing system library and install it. ## UnsupportedClassVersionError error When I run the Java action, the "UnsupportedClassVersionError" error occurs. #### Cause When it was compiled in the higher version than the Cloud Functions action runtime version, this error may occur. #### Solution How to check the compiled version of the action you uploaded is as follows: Assume that the main class is Hello and you are executing it in the Linux environment. 1. To download the JAR file, click **[Edit]** in the Action menu and click **[Download]**. 2. Enter the following command to decompress the JAR file: ``` $ jar xf ``` 3. Enter the following command to check the compile version of the class file: It has to be same or lower than the action runtime version. - Unix/Linux environment ``` $ file Hello.class Hello.class: compiled Java class data, version 52.0 (Java 1.8) or $ javap -verbose Hello | grep "major" major version: 52 ``` - Windows environment ``` $ javap -verbose Hello | findstr "major" major version: 52 ``` Note For more information about creating and using Java actions, see Cloud Functions examples > Create and utilize actions by runtime > [Java](/docs/en/cloudfunctions-example-java). ## Too many concurrent requests in flight()'response returned As a result of action, a response like "Too many concurrent requests in flight()'" has returned. #### Cause The default concurrent value is exceeded. #### Solution See [Cloud Functions prerequisites](/docs/en/cloudfunctions-spec) to edit the number of concurrent actions that can be executed. If you need to increase the default concurrent value, contact [Customer Support](https://www.ncloud.com/support/question/service) of NAVER Cloud Platform. Note If you're still having trouble finding what you need, click on the feedback icon and send us your thoughts and requests. We'll use your feedback to improve this guide.