# Data Model does not work
**URL:** https://forum.builder.io/t/data-model-does-not-work/69
**Category:** Technical Questions
**Created:** [May 4, 2020, 2:26pm UTC](https://forum.builder.io/t/data-model-does-not-work/69 "2020-05-04T14:26:02Z")
**Posts on this page:** 3
**Page:** 1
### Author:  [@Igor](https://forum.builder.io/u/Igor)
#### Post date: [May 4, 2020, 2:26pm UTC](https://forum.builder.io/t/data-model-does-not-work/69/1 "2020-05-04T14:26:03Z")
I created a date model with some objects, some mandatory, some not, etc., but when I create in “content” the console shows this error below, and the interface does not change
Uncaught (in promise) Error: [mobx-state-tree] Cannot add an object to a state tree if it is already part of the same or another state tree. Tried to assign an object to ‘/data/brand’, but it lives already at ‘/models/result/2/fields/0/defaultValue’
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### Author:  [@korey](https://forum.builder.io/u/korey)
#### Post date: [May 4, 2020, 4:54pm UTC](https://forum.builder.io/t/data-model-does-not-work/69/2 "2020-05-04T16:54:19Z")
Sounds like you might be running into a bug with the data model. Can you provide some more information so we can try to reproduce the issue? What does your data model look like (what fields do you have, what types are they, etc.)?
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### Author:  [@Igor](https://forum.builder.io/u/Igor)
#### Post date: [May 4, 2020, 5:13pm UTC](https://forum.builder.io/t/data-model-does-not-work/69/3 "2020-05-04T17:13:06Z")
I don’t know if you can access it, but this is the model: [https://builder.io/models/efc3a2bb2c09419889f0bc13b60047a2](https://builder.io/models/efc3a2bb2c09419889f0bc13b60047a2)
the fields is:
