Can not upload plugin

[zelo2000]

Preflight Checklist

• I agree to follow the Code of Conduct that this project adheres to.
• I have searched the issue tracker for a feature request that matches the one I want to file, without success.

Describe the bug
Try to upload sample plugin but it is don't uploaded and throw error in to the console.

To Reproduce
Steps to reproduce the behavior:

1. Go to 'Extras'
2. Click on 'Plugin'
3. Click on 'Add'
4. Click on 'Custom'
5. Insert URL
6. Click on 'Add'
7. Click on 'Apply'
8. Click on 'Ok'
9. Reload the app
10. See error

Expected behavior
The plugin must be successfully uploaded.

Screenshots

• draw.io version: 13.10.3

Desktop:

• OS: windows
• Browser: chrome
• Version: 86.0.4240.198

[davidjgraph]

What is the URL?

[zelo2000]

https://www.draw.io/plugins/p1.js

[davidjgraph]

Try https://app.diagrams.net/plugins/...

[zelo2000]

It's work. But how should URL looks like if I want to add custom plugin?
I try use https://62410566428e.ngrok.io/drawio.js

[zelo2000]

Also I tried to upload plugin from dropbox using this URL https://www.dropbox.com/s/re6yfkh7crttjl1/p1.js?dl=0
And I have same error as in first message.

[davidjgraph]

Yes, since adding a CSP to the site third-party plugins cannot load, see #958.

We don't currently have an obvious solution to that. The long term suggestion will be to deploy your own version with a plugin, or use the desktop version jgraph/drawio-desktop#139.