The most common culprit is the OneDrive sync client falling out of sync with the server. Restart the OneDrive process, sign out and back in, then force a manual sync. If a specific file is stuck, check whether someone else has it open — SharePoint locks files during active editing sessions.
Before assuming the problem is on the server side, clear your browser cache and cookies, then try an incognito window. If that works, the issue is stored credentials or a corrupted session token. On desktop, go to Windows Credential Manager and remove any saved SharePoint entries, then log in fresh.
Slow page loads usually come down to one of three things:
If search suddenly stops returning files you know exist, the index is likely stale. New or recently modified files can take up to 24 hours to get indexed. For site admins, triggering a manual re-index from Site Settings helps speed things up. Also check whether the file is stored in a location excluded from search scope.
You click a shared link and get 'Access Denied' even though someone explicitly shared it with you. This usually means the item-level permission was set but the parent site or library didn't propagate access correctly. Ask the owner to reshare directly from the document level rather than the folder, or have an admin check the permission inheritance chain.
After uploading, the file doesn't show in the library. Refresh the page first — SharePoint's list view doesn't always auto-update. If the file is still missing, check the recycle bin and version history; uploads occasionally fail mid-transfer and leave no trace without an error message.