Hello Nicky, this is Emily.
When you see a red x icon on your OneDrive icon, it usually indicates that there can be a conflict for a certain file or folder.
If you click on the OneDrive icon on the lower right on your taskbar, it should launch a small pop up. If everything is good, it should say "Your files are synced" with a green check icon. Otherwise, it should tell you which files are in conflict. Let me see if that's what you can see first.