My iMovie project won't export to photo gallery

well I made a 23 min video on i movie on my iPad so once I finashed I went to the upload bit a pressed upload to YouTube. But it said cannot upload a video over 15 min to iCloud so I didn't know how to fix that but i did know how to upload on the photo gallery so I pressed save video and it said exporting so I left my iPad on on charge and came back about 1 hour later because i had to eat dinner came back to say that un able to export unknown error. How can I upload the video to YouTube now? I can't find it on ifunbox or iTunes please help