Error while editing mockup design

Step to reproduce:

have a project created
have a mockup created
open the mockup
edit design
save design current behaviour It throws this error {"data":{"error":"E_UNKNOWN","status":500,"summary":"Encountered an {"unexpected error","raw":{}},"status":500,"config":{"method":"PUT","transfor {"mRequest":[null],"transformResponse":[null],"jsonpCallbackParam":"callback" {","data":{"project":{"name":"Project 1","description":"This is a project {"where I will work mockups","imgToShow":"","userId":"58c33d285ee671461ef98fa {"2","state":"New","type":"Design","createdAt":"2017-03-11T00:00:15.495Z","up {"datedAt":"2017-05-02T13:57:03.746Z","id":"58c33e0f5ee671461ef98fa4"},"owner {"":{"email":"admin22@gmail.com","createdAt":"2017-03-06T19:56:39.337Z","upda {"tedAt":"2017-03-09T18:54:15.779Z","firstName":"Admin22","lastName":"Last {"Name","username":"admin22","id":"58bdbef7311a776d1f712711"},"name":"Mockup {"002","width":"880","height":"400","state":"New","description":"","imgToShow {"":"http://blogs.atlassian.com/news/2009/09/10/SimpleLoginScreen-thumb-250x1 {"79.png","createdAt":"2017-03-23T15:55:32.817Z","updatedAt":"2017-05-02T13:5 {"7:03.661Z","links":[],"id":"58d3eff4a3ea8ec436fde7a9"},"url":"http://localh {"ost:1337/mockup/58d3eff4a3ea8ec436fde7a9","headers":{"Accept":"application/ {"json, text/plain, /","Content-Type":"application/json;charset=utf-8"},"wi {"thCredentials":true},"statusText":"Internal Server Error"}

Expected result: Save mockup design without throwing any error

kapit4n / mockupero-api