Lightroom is not exporting videos anymore

I was exporting videos normally on Lightroom until a few minutes ago. I just finished exporting one video and when I started to export the new one, Lightroom is like exporting the video forever the loading bar is not advancing anymore and it is now happening everytime I try to export a video even one I've already exported before! Anyone can help? I have a deadline and I'm desperate! Video files appear like in the attached image.