Error Messaging in PHP by create Entry

Hello,
i’m currently working on an importer based on PHP for custom XML structures.
Sometimes if i try to import a new Entry like this JSON below
{"sys":{"type":"Entry","contentType":{"sys":{"type":"Link","id":"activities","linkType":"ContentType"}}},"fields":{"activityId":{"de-DE":"134390"},"activityCategoryId":{"de-DE":{"id":"6k6oWNkBXi2CEIigSuqq--","type":"Link"}},"productionId":{"de-DE":{"id":"2qeEQNvx0kys6MkYY22O--","type":"Link"}},"stageId":{"de-DE":{"id":"4dflsFvYiQQWYoqiA6e4Ic","type":"Link"}},"date":{"de-DE":"2018-09-25T15:30:00.000000"},"startTime":{"de-DE":"15:30"},"endTime":{"de-DE":"18:30"},"printStartTime":{"de-DE":true},"printEndTime":{"de-DE":"true"},"alternativeTitle":{"de-DE":"apoBank mit F\u00fchrungen 16:15 + 18:30"}}}

ContentModel Structure
{"name":"Activities","description":"","displayField":"alternativeTitle","fields":[{"id":"activityId","name":"ActivityId","type":"Integer","localized":false,"required":false,"validations":[],"disabled":false,"omitted":false},{"id":"activityCategoryId","name":"ActivityCategoryId","type":"Link","localized":false,"required":false,"validations":[],"disabled":false,"omitted":false,"linkType":"Entry"},{"id":"productionId","name":"ProductionId","type":"Link","localized":false,"required":false,"validations":[],"disabled":false,"omitted":false,"linkType":"Entry"},{"id":"stageId","name":"StageId","type":"Link","localized":false,"required":false,"validations":[],"disabled":false,"omitted":false,"linkType":"Entry"},{"id":"printStartTime","name":"PrintStartTime","type":"Boolean","localized":false,"required":false,"validations":[],"disabled":false,"omitted":false},{"id":"printEndTime","name":"PrintEndTime","type":"Boolean","localized":false,"required":false,"validations":[],"disabled":false,"omitted":false},{"id":"alternativeTitle","name":"AlternativeTitle","type":"Symbol","localized":false,"required":false,"validations":[],"disabled":false,"omitted":false},{"id":"priceGroupId","name":"PriceGroupId","type":"Link","localized":false,"required":false,"validations":[],"disabled":false,"omitted":false,"linkType":"Entry"},{"id":"date","name":"Date","type":"Symbol","localized":false,"required":false,"validations":[],"disabled":false,"omitted":false},{"id":"startTime","name":"Start Time","type":"Symbol","localized":false,"required":false,"validations":[],"disabled":false,"omitted":false},{"id":"endTime","name":"End Time","type":"Symbol","localized":false,"required":false,"validations":[],"disabled":false,"omitted":false}]}

I got an unclear Validation Error. Nothing else only that.
Is it possible to burn the current Messages and give me an advise how to finde the real reason why i got an validation Error?

Could please anyone tell me why i got this Error?

Problem is solved!

i forgott the LinkType.

array(‘sys’ => array(‘id’ => ‘’,‘type’ => ‘Link’, ‘linkType’ => ‘Entry’));

that is the correct structure for PHP.

thanks @Julie Creating entry with associated resource specified

she founded the correct JSON to do that.