Occasionally, YouTube rejects VP-direct exports, ostensibly due to data limits. Uploading in the middle of the night may prove successful.
Save your work as an mp4 file, then use the YT uploader. https://support.google.com/youtube/answer/57407?co=GENIE.Platform%3DDesktop&hl=en
Does that succeed?
As for editing, Save Project File AS routinely, giving it a unique # or name, so as not to overwrite prior saves. Using Save Project Files (no AS) will overwrite. Then you can restore a project to the state it was in when saved. Just double-click the VPJ file (which isn't playable).