Cannot upload file in Kanban Attachments

Hello webix support ,
I want to upload attachments in kanban TaskBoard , but I keep getting Error 405 (Method not allowed) , I tried to add Header to allow origins but it seems not working , I’m using trial version before buying the webix full commercial version

Hello, @Oussama

This behavior with a high probability caused by the weak backend.
As a client-side UI library, Webix does not have any requirements for the backend technology and architecture except the request/response formats. The basic description of the loading and saving patterns is described in the related docs chapter.
https://docs.webix.com/kanban__loading_data.html

Best regards