Error in Content Fragment Model

Hi,

I'm working on AEM as a Cloud Service and in that I'm creating a content fragment model. But after adding a certain number of fields in the model, when I try to save the model, it shows empty. Adding the image for reference:

But the field which I have created in present in model. I verified this by creating a content fragment from this model and all the fields are present in it. Also, after adding the fields after which the model fields disapper, an error is logged in error.log. Image for the reference:

Is there any limit to number of fields to be added in content fragment model. Any help would be appreciated. 

Thanks