# Error when developing plugin in Kibana 8.9 (master branch) and 8.6

**URL:** <https://discuss.elastic.co/t/error-when-developing-plugin-in-kibana-8-9-master-branch-and-8-6/335742>\
**Category:** Kibana\
**Tags:** kibana-plugin-development\
**Created:** [June 12, 2023, 7:30am UTC](https://discuss.elastic.co/t/error-when-developing-plugin-in-kibana-8-9-master-branch-and-8-6/335742 "2023-06-12T07:30:11Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![Sheereen](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/sheereen/32/122005_2.png) [@Sheereen](https://discuss.elastic.co/u/Sheereen)\
**Post date:** [June 12, 2023, 7:30am UTC](https://discuss.elastic.co/t/error-when-developing-plugin-in-kibana-8-9-master-branch-and-8-6/335742/1 "2023-06-12T07:30:11Z")

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Hi,

I was working on a custom plugin in 8.5.3. It was working fine. Even new plugin generation, etc... all were smooth in 8.5.3.

I had tried the same on 8.6... and now in 8.9. In both these versions, I just generated a helloWorld plugin using the generate\_plugin script. The plugins were generated but, both returned error on kibana browser load.

```auto
Refused to execute script from 'http://<ip>:5600/nzf/9007199254740991/bundles/plugin/hello/1.0.0/hello.plugin.js' because its MIME type ('application/json') is not executable, and strict MIME type checking is enabled.

```

Please refer to this link also ([Kibana plugin development: Error when creating plugin in Kibana 8.6](https://discuss.elastic.co/t/kibana-plugin-development-error-when-creating-plugin-in-kibana-8-6/329264))

Thanks

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<div class="post-metadata">

**Author:** ![Jennamartin3](https://avatars.discourse-cdn.com/v4/letter/j/34f0e0/32.png) [@Jennamartin3](https://discuss.elastic.co/u/Jennamartin3)\
**Post date:** [June 12, 2023, 9:19am UTC](https://discuss.elastic.co/t/error-when-developing-plugin-in-kibana-8-9-master-branch-and-8-6/335742/2 "2023-06-12T09:19:16Z")

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You have to check your Kibana version compatibility, verify your plugin configuration, Clear browser cache, Review your plugin code.

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<div class="post-metadata">

**Author:** ![system](https://us1.discourse-cdn.com/elastic/original/3X/1/a/1ac57faf039f6b580b3f104ef42a2a89e41014de.png) [@system](https://discuss.elastic.co/u/system)\
**Post date:** [July 10, 2023, 9:20am UTC](https://discuss.elastic.co/t/error-when-developing-plugin-in-kibana-8-9-master-branch-and-8-6/335742/3 "2023-07-10T09:20:15Z")

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