"The document cannot be processed since it contains unexpected content".

This is the message when I try to open a Word file in Studio. This file is inside a package I received. I've checked the several topics on this forum about this kind of error but since I didn't create the package myself, the advice already posted is not really helpful.

I'm using Trados Studio 2019. The File Type Identifier reads "WordprocessingML v.2".

Can you help me here?

Thanks.