Nintex Forms with SharePoint 2019 On-Perm fails to publish or Save

Can you add any screenshots so that more people can better understand the issue at hand? 

Hi @tam82 

If you don't find a solution for this, could you please share the screenshots of the issue you're having with suppot@nintex.com

Thanks,

Sumit

I cannot provide a screenshot 

When i hit publish i get a popup 

Nintex Form:"Request Error" (XHTML DTD Pop-Up)

<?xml version= "1.0" encoding="utf-8">

<!DOCTYPE html Public "-//W3C/DTD XHTML 1.0 Translational//EN"

Request Error

Just found this is only an issue on Modern Communication Sites 

I was able to get it to work on a Modern Team Site