OneNote can’t sync notebooks when you’ve run out of storage space. To fix this problem, first verify whether the notebook is stored on OneDrive or on SharePoint. OneDrive URLs will typically contain some variation of OneDrive.live.com, while SharePoint URLs are likely customized by the server administrator in your organization.
If your notebook is stored on OneDrive, check to see how much free space you have left for your account. If you are almost or completely out of space, consider deleting some older files that you no longer need, or purchase more OneDrive storage space to resolve the issue.
If your notebook is stored on SharePoint, you may have exceeded the storage quota that’s been allocated to you. Please contact the SharePoint or IT administrator in your organization to resolve the issue.
Notebooks that are stored on OneDrive or SharePoint are also cached locally on your computer. If you’re running out of disk space on your computer, the error may also appear. To free up space for your notebooks, consider deleting some files that you no longer need.
If you have plenty of storage space left and you are still seeing this error message, please report this issue in the OneNote forums on Microsoft Answers so we can investigate the cause and find a solution.