Export problem (file size)

Hello there ! 
That's the first time I face this problem. I'm trying to export a 26 min video, but the estimated file size is 80 ko ! And the lenght of the video is not recognized (00;00;00;00) instead of those 26 min.
Usually, I can export without any problem, and I always use the same YouTube 1080 settings... 😞
Please, help! Where does it may come from? Thank you!