Unknown format error

I am trying to load a .prt file into Tetra4D Reviewer to export as a 3D PDF. I have done this in the past. But for some reason, the current file is throwing this warning. Not sure where to begin with troubleshooting my file as it is certainly a file Tetra should be able to read.

Hi,

Your file looks to be a NX file, and it could be a version issue. Please contact us at the support, through the Customer Portal or via an email. e will review with you your version, and the version of your NX file.

Thanks,

The Support Team