1. Check your OneDrive and SharePoint Settings to look for any possible discrepancies.
2. Check to make sure that your OneDrive share permissions were properly set up.
3. Check the Activity tab to see if there are any errors or conflicts.
4. Run a diagnostic on your browser and uninstall as needed.
5. Make sure the OneDrive for Business client is up to date.
6. Sign out of the OneDrive client and try signing back in.