Why do I get error code 400 when I Post Topic to D2L?

Url: "https://partners.brightspace.com/d2l/api/le/1.12/10593/content/modules/366347/structure/?x_a=......................."request body (as described here):{"Title":"123","ShortTitle":"","Type":1,"TopicType":3,"Url":"/d2l/common/dialogs/quickLink/quickLink.d2l?ou=10593&type=lti&rcode=04E1284B-7166-4938-B8A7-6F359D1AA5FC-195613&srcou=10593","StartDate":null,"EndDate":null,"DueDate":null,"IsHidden":false,"IsLocked":false,"OpenAsExternalResource":false,"Description":{"Text":"","Html":""},"MajorUpdate":null,"MajorUpdateText":"","ResetCompletionTracking":null,"Duration":null}  response:{"type":"http://docs.valence.desire2learn.com/res/apiprop.html#invalid-parameters","title":"Invalid Parameters","status":400,"detail":"Request has missing or invalid parameters."} The module id 366347 exists in course content. I also tried to change Description value to null, but have the same result.Note that GET request to "https://partners.brightspace.com/d2l/api/le/1.12/10593/content/modules/366347/structure/?x_a=......................." successfully returns data with status 200 OK . Also there were no problems with POST requests to other API paths. Thank you!