@LMCP Hi. Sorry to hear you’re experiencing issues. If you have Windows 10, please follow this guide and its recommendations first to make your OS is not choking external third party programs in general. If needed please re-download the software again, unblock and unzip the files as indicated: [Guide] How to Train Your Pencil2D (Windows)
Later then please follow the steps on this reply (it has GIF’s) in order to make sure you are able to export with the appropriate extension, this is to rule out you’re experiencing this issue: I'm not able seeing things I have exported