Running Nintex form Validations and SharePoint OOTB validation. Is it possible?

Hi,

 I have a SharePoint 2013 list with various columns present in it.

I have few validations in Nintex forms and as well as SharePoint OOTB.

But when I try to fire the validations which are specified in SharePoint OOTB validations, the pop up error message does not appear, as well as,

the item is not saved.

When I try to fire the validations in Nintex forms, it works as expected.

What is the issue here? Can I not run the Nintex form validations and SharePoint OOTB validations simultaneously?

Thanks in advance.