When saving a value from a custom property editor, I get this error (image 2): If I save without a input value, it works fine though (image 1). Any ideas how to fix this? I have been following the instructions from the docs: https://docs.umbraco.com/umbraco-cms/tutorials/creating-a-property-editor , both for the suggestion.ts, and the settings in umbraco-package.json https://cdn.discordapp.com/attachments/1331918325344899115/1331918325571260456/bilde.png?ex=67935d1a&is=67920b9a&hm=e4bbe326204478c1ad8a407752f3bbe64d8973e94920ef0c292afaa81f14f747& https://cdn.discordapp.com/attachments/1331918325344899115/1331918326129098752/bilde.png?ex=67935d1a&is=67920b9a&hm=5695730a5c48a7e1c313225f62b1aaacbb65cc33d6bd621f8fd5e580c463dc91&

It seems like you feed the 'wrong' data to the endpoint, maybe you can check your endpoint in Swagger (or a tool like Postman or Insomnia) so you have a playground you can test the calls to and see if you miss anything.

Thanx for the tip, will try that!