# Error when loading CZML

**URL:** <https://community.cesium.com/t/error-when-loading-czml/21427>\
**Category:** CesiumJS\
**Created:** [December 5, 2022, 2:09am UTC](https://community.cesium.com/t/error-when-loading-czml/21427 "2022-12-05T02:09:51Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![chan](https://sea2.discourse-cdn.com/cesium/user_avatar/community.cesium.com/chan/32/9891_2.png) [@chan](https://community.cesium.com/u/chan)\
**Post date:** [December 5, 2022, 2:09am UTC](https://community.cesium.com/t/error-when-loading-czml/21427/1 "2022-12-05T02:09:51Z")

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I linked sql in cjs file and sent czml file to js file by ajax.

And I proceeded with dataSource.load(czml),

“DeveloperError {name: ‘DeveloperError’, message: ‘czml is required.’”

The error appears like this: Any workaround?  
Thank you so much for your help.

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<div class="post-metadata">

**Author:** ![Gabby\_Getz](https://sea2.discourse-cdn.com/cesium/user_avatar/community.cesium.com/gabby_getz/32/7838_2.png) [@Gabby\_Getz](https://community.cesium.com/u/Gabby_Getz)\
**Post date:** [December 13, 2022, 2:19pm UTC](https://community.cesium.com/t/error-when-loading-czml/21427/2 "2022-12-13T14:19:40Z")

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Hi there,

In the line `dataSource.load(czml)`, the `czml` variable is likely `undefined` or `null`.