# 599 error KX Sandbox

**URL:** <https://forum.kx.com/t/599-error-kx-sandbox/14229>\
**Category:** Academy Support\
**Tags:** imported\
**Created:** [May 29, 2025, 12:38pm UTC](https://forum.kx.com/t/599-error-kx-sandbox/14229 "2025-05-29T12:38:37Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![proof](https://sea2.discourse-cdn.com/flex002/user_avatar/forum.kx.com/proof/32/128_2.png) [@proof](https://forum.kx.com/u/proof)\
**Post date:** [May 29, 2025, 12:38pm UTC](https://forum.kx.com/t/599-error-kx-sandbox/14229/1 "2025-05-29T12:38:37Z")

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[https://learninghub.kx.com/forums/topic/599-error-kx-sandbox](https://learninghub.kx.com/forums/topic/599-error-kx-sandbox)

I was able to work on the Inter-Process Communication sandbox and I only had an exercise or two left to do. Now, I cannot open the sandbox for neither the

1. Inter-Process Communication; nor

2. kdb developer level 2 Capstone Project

I can still access and work on the Jupyter notebooks from previous modules. Any help with this issue would be appreciated.

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**Author:** ![mmcparland](https://sea2.discourse-cdn.com/flex002/user_avatar/forum.kx.com/mmcparland/32/54_2.png) [@mmcparland](https://forum.kx.com/u/mmcparland)\
**Post date:** [May 29, 2025, 1:15pm UTC](https://forum.kx.com/t/599-error-kx-sandbox/14229/2 "2025-05-29T13:15:59Z")

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Hi @proof&nbsp;

Can I suggest restarting your server?

Go to File -\> Hub Control and here you will see the options to **Stop Server** and **Start Server** again.

Let me know if this works!

Thanks.

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**Author:** ![proof](https://sea2.discourse-cdn.com/flex002/user_avatar/forum.kx.com/proof/32/128_2.png) [@proof](https://forum.kx.com/u/proof)\
**Post date:** [May 29, 2025, 1:17pm UTC](https://forum.kx.com/t/599-error-kx-sandbox/14229/3 "2025-05-29T13:17:03Z")

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I just did that and then saw your message. It worked, thank you very much!

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**Author:** ![proof](https://sea2.discourse-cdn.com/flex002/user_avatar/forum.kx.com/proof/32/128_2.png) [@proof](https://forum.kx.com/u/proof)\
**Post date:** [May 29, 2025, 1:23pm UTC](https://forum.kx.com/t/599-error-kx-sandbox/14229/4 "2025-05-29T13:23:04Z")

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I thought I had done something wrong to cause it to crash, but I just looked at the solution and it's the same thing. I ran it and now have to restart my server again. I am sharing in case this is a common issue!  
  
Code (from IPC\_Exercise\_Solution) that seems to cause the crash:

handleBack `ID

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<div class="post-metadata">

**Author:** ![mmcparland](https://sea2.discourse-cdn.com/flex002/user_avatar/forum.kx.com/mmcparland/32/54_2.png) [@mmcparland](https://forum.kx.com/u/mmcparland)\
**Post date:** [May 29, 2025, 1:24pm UTC](https://forum.kx.com/t/599-error-kx-sandbox/14229/5 "2025-05-29T13:24:08Z")

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Thank you for raising! I'll make sure to have a look at this :)&nbsp;