My videos won't upload to YouTube

I need help ASAP! So I figured out how to export through the app. It only works about 50% of the time. Then it will take HOURS for the exporting, then when I upload to YouTube about 70% of the time it doesn't process or upload correctly and will cut out parts of my videos. It's very frustrating. I've never been able to upload straight to YouTube. It says there is an error proccessing the video and it won't tell me what the issue is. I've tried contacting help through YouTube and no one has gotten back to me. It's frustrating. I'm very new so I'm probably just doing something simple wrong.  PLEASE HELP! 😞