# Error: Wrong MIME type

**URL:** <https://kanboard.discourse.group/t/error-wrong-mime-type/558>\
**Category:** Plugins\
**Created:** [July 29, 2019, 8:20am UTC](https://kanboard.discourse.group/t/error-wrong-mime-type/558 "2019-07-29T08:20:28Z")\
**Posts on this page:** 8\
**Page:** 1

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**Author:** ![av-ipunkt](https://avatars.discourse-cdn.com/v4/letter/a/a87d85/32.png) [@av-ipunkt](https://kanboard.discourse.group/u/av-ipunkt)\
**Post date:** [July 29, 2019, 8:20am UTC](https://kanboard.discourse.group/t/error-wrong-mime-type/558/1 "2019-07-29T08:20:28Z")

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Hi guys,  
I need your support by debugging.  
I’ve managed to join [Offline app](https://github.hubspot.com/offline/docs/welcome/) with Kanboard.  
This Plugin is available under this [link](https://github.com/ipunkt/OfflineKanboardPlugin).

The thing is: my colleague received an error after installing the plugin:

> ```
> Refused to execute script from 'https:// ****** /js/offline?' because its MIME type ('text/html') is 
> not executable, and strict MIME type checking is enabled.
> 
> ```

I cannot reproduce this error by me locally, it works as it was planned and developed. I suppose this error appears somehow only by installing on other clients.

If someone has free 10 min to install this plugin and test it a little bit, I would much appreciate your solidarity.

P.S. I am not a professional developer, that’s why this bug can be a very simple thing. I’ve googled for this issue, but could not find any useful topics.

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**Author:** ![av-ipunkt](https://avatars.discourse-cdn.com/v4/letter/a/a87d85/32.png) [@av-ipunkt](https://kanboard.discourse.group/u/av-ipunkt)\
**Post date:** [July 29, 2019, 11:20am UTC](https://kanboard.discourse.group/t/error-wrong-mime-type/558/2 "2019-07-29T11:20:24Z")

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It has to be Content-Type: “text/javascript”, but it sends “text/html”

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**Author:** ![creecros](https://yyz2.discourse-cdn.com/free1/user_avatar/kanboard.discourse.group/creecros/32/156_2.png) [@creecros](https://kanboard.discourse.group/u/creecros)\
**Post date:** [July 30, 2019, 12:25am UTC](https://kanboard.discourse.group/t/error-wrong-mime-type/558/3 "2019-07-30T00:25:31Z")

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Only guessing…

Cache.

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<div class="post-metadata">

**Author:** ![av-ipunkt](https://avatars.discourse-cdn.com/v4/letter/a/a87d85/32.png) [@av-ipunkt](https://kanboard.discourse.group/u/av-ipunkt)\
**Post date:** [July 30, 2019, 6:31am UTC](https://kanboard.discourse.group/t/error-wrong-mime-type/558/4 "2019-07-30T06:31:46Z")

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Could you install and test it a bit?  
btw, I’ve made a [plugin](https://github.com/ipunkt/KanboardSearchPlugin) using yours as an example

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<div class="post-metadata">

**Author:** ![av-ipunkt](https://avatars.discourse-cdn.com/v4/letter/a/a87d85/32.png) [@av-ipunkt](https://kanboard.discourse.group/u/av-ipunkt)\
**Post date:** [July 30, 2019, 1:33pm UTC](https://kanboard.discourse.group/t/error-wrong-mime-type/558/5 "2019-07-30T13:33:01Z")

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yeap. seems that the issue was in cache.  
Thanks @creecros!  
The topic can be now closed.

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**Author:** ![creecros](https://yyz2.discourse-cdn.com/free1/user_avatar/kanboard.discourse.group/creecros/32/156_2.png) [@creecros](https://kanboard.discourse.group/u/creecros)\
**Post date:** [July 30, 2019, 6:29pm UTC](https://kanboard.discourse.group/t/error-wrong-mime-type/558/6 "2019-07-30T18:29:57Z")

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A rancher user? I’m not alone…

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<div class="post-metadata">

**Author:** ![av-ipunkt](https://avatars.discourse-cdn.com/v4/letter/a/a87d85/32.png) [@av-ipunkt](https://kanboard.discourse.group/u/av-ipunkt)\
**Post date:** [August 1, 2019, 11:21am UTC](https://kanboard.discourse.group/t/error-wrong-mime-type/558/7 "2019-08-01T11:21:41Z")

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@creecros  
nope, cache deletion didn’t help, the problem is not yet solved (

one more thing, this plugin prevents adding anything to Kanboard/Projects (such as tasks, new Projects and so on) when it is activated. Don’t understand anything…

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<div class="post-metadata">

**Author:** ![av-ipunkt](https://avatars.discourse-cdn.com/v4/letter/a/a87d85/32.png) [@av-ipunkt](https://kanboard.discourse.group/u/av-ipunkt)\
**Post date:** [August 1, 2019, 12:31pm UTC](https://kanboard.discourse.group/t/error-wrong-mime-type/558/8 "2019-08-01T12:31:00Z")

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The Problem is at this line:  
`$this->hook->on("template:layout:js", array("template" => "js/offline"));`